JP2023085339A - Stereo signal processing method and device - Google Patents

Abstract

To provide a stereo signal processing method and device.SOLUTION: A method includes the steps of: acquiring a PCM signal including a first channel signal and a second channel signal of a multi-channel signal of a current frame including a stereo signal; acquiring first ITD representing a time difference between the first channel signal and the second channel signal; determining whether the sign of the first ITD is the same as the sign of second ITD representing a time difference between two channel signals of the last frame; executing first delay alignment processing on the first channel signal based upon the first ITD when the sign of the first ITD is different from the sign of the second ITD, and executing second delay alignment processing on the second channel signal based upon the second ITD.SELECTED DRAWING: Figure 1

Description

[Cross reference to related application]
This application claims priority to Chinese Patent Application No. 201710344704.4 entitled "STEREO SIGNAL PROCESSING METHOD AND APPARATUS" filed with the Chinese Patent Office on May 16, 2017, the entire contents of which are incorporated by reference. do.

[Technical field]
This application relates to the field of information technology, and more particularly to a stereo signal processing method and apparatus.

As the quality of life improves, people are increasing their demand for high quality audio. Compared to monophonic audio, stereo audio provides a sense of direction and distribution for each sound source, providing improved clarity, intelligibility, and immersiveness of information. Stereo audio is therefore very popular. In existing time domain stereo coding techniques, left and right channel signals are usually downmixed into Mid channel and Side channel signals in the time domain. A downmixed mid-channel signal may be denoted as 0.5×(L+R), which represents the relevant information between the left and right channel signals. A downmixed side channel signal may be denoted as 0.5×(L−R), which represents the differential information between the left and right channel signals. L indicates the left channel signal and R indicates the right channel signal. The mid-channel and side-channel signals are then encoded separately by using a mono-channel encoding method. Mid-channel signals are typically encoded using a relatively large amount of bits, and side-channel signals are typically encoded using a relatively small amount of bits.

To improve coding efficiency, the mid-channel signal should be larger and the side-channel signal should be smaller. Currently, in time-domain stereo coding, the matching algorithm performs delay estimation on the left and right channel signals to obtain the inter-channel time difference before the mid-channel and side-channel signals are obtained. , a delay alignment process is performed on the left and right channel signals based on the inter-channel time difference, resulting in a larger downmixed mid-channel signal and a downmixed side channel signal becomes smaller. In algorithms for performing delay alignment based on the time difference between channels, typically one channel is selected from the left and right channels and the delay alignment process is performed on the channel's signal. This channel is called the target channel. No delay adjustment is performed on the other channel's signal, and the other channel is used as a reference for delay adjustment to the target channel. This channel is called the reference channel.

In the existing method, if the sign of the inter-channel time difference of the current frame obtained through delay estimation is found to be different from the sign of the inter-channel time difference of the previous frame, the selection of the target channel of the current frame is the previous frame target channel selection remains the same. In addition, regardless of the current frame's inter-channel time difference estimate, the current frame's inter-channel time difference is forced to zero. Then, the delay alignment process is based on the inter-channel time difference set to zero to ensure that the delay between the target channel and the reference channel of the current frame after the delay alignment process is zero: Executed on the target channel of the current frame.

In the above method, when the sign of the inter-channel time difference of two frames of a stereo signal changes, this indicates that the order of arrival of the left and right channel signals changes, with the left channel signal originally arriving first. Alternatively, the right channel signal may arrive first, or the left channel signal may arrive first instead of the right channel signal originally arriving first. If the inter-channel time difference for the current frame is forced to zero, the left and right channels are adjusted based on the zero time difference rather than the actual time difference between the left and right channels, resulting in a time domain downmix. Processing is performed on the left and right channel signals thus obtained and obtained after delay adjustment. However, in practice, actual delay alignment is not achieved for two channel signals. Therefore, there is no effective method to offset the correlation component between the two channels, resulting in increased energy of the side-channel signal in the current frame after time-domain downmixing, resulting in an overall Stereo encoding quality is reduced.

This application aims to solve the problem of low encoding quality in stereo encoding caused by inter-channel delays not being aligned when the sign of the inter-channel time difference between two frames of a stereo signal changes. A processing method and apparatus are provided.

An embodiment of this application provides a stereo signal processing method applied on the encoder side of a stereo codec, the method comprising:
The step of performing delay estimation on the current frame stereo signal to determine the current frame inter-channel time difference, wherein the current frame inter-channel time difference is between the current frame first channel signal and a step, which is the time difference between the current frame and the second channel signal;
For the first channel signal of the current frame based on the inter-channel time difference of the current frame, if the sign of the inter-channel time difference of the current frame is different from the sign of the inter-channel time difference of the frame before the current frame performing delay alignment processing and performing delay alignment processing on the second channel signal of the current frame based on the inter-channel time difference of the previous frame, wherein the first channel signal is the current frame's A target channel signal, the second channel signal being on the same channel as the target channel signal of the previous frame.

According to the method provided in this application, when it is determined that the sign of the inter-channel time difference of the current frame is different from the sign of the inter-channel time difference of the previous frame of the current frame, the delay alignment process The delay alignment process is performed on the first channel signal of the current frame based on the inter-channel time difference of the frame, and the delay alignment process is performed on the second channel signal of the current frame based on the inter-channel time difference of the previous frame. executed. Therefore, the delay alignment processing of the current frame can be performed based on the actual inter-channel time difference, thereby ensuring a better alignment effect, and the inter-channel time difference of the current frame is forced to zero. , the correlation component between the two channels of the current frame after the delay alignment process cannot be offset, and as a result the energy of the secondary channel signal of the current frame after the time domain downmix increases, resulting in an overall avoiding the prior art problem of affecting the coding quality of

Optionally, performing delay alignment processing on the first channel signal of the current frame based on the inter-channel time difference of the current frame comprises:
The signal of the first processing length in the first channel signal of the current frame is changed to the signal of the first alignment processing length to obtain the first channel signal of the current frame after the delay alignment processing. compress,
The first process length is determined based on the inter-channel time difference of the current frame and the first alignment process length, wherein the first process length is greater than the first alignment process length.

Optionally, the first process length is the sum of the absolute value of the inter-channel time difference of the current frame and the first alignment process length.

Optionally, the starting point of the signal of the first treatment length is located before the starting point of the signal of the first alignment treatment length, such that the starting point of the signal of the first treatment length and the first alignment treatment length is the absolute value of the inter-channel time difference of the current frame.

Optionally, the starting point of the signal of the first alignment process length is located at the starting point of the first channel signal of the current frame or after the starting point of the first channel signal of the current frame, The length between the start point of the alignment process length signal and the end point of the first channel signal of the current frame is greater than or equal to the first alignment process length.

Optionally, the starting point of the signal of the first alignment process length is located before the starting point of the first channel signal of the current frame, and the starting point of the signal of the first alignment process length and the current frame is less than or equal to the transition length, and between the start point of the signal of the first alignment process length and the end point of the first channel signal of the current frame is greater than or equal to the sum of the length of the first alignment process and the transition length, and the transition length is less than or equal to the maximum absolute value of the inter-channel time difference of the current frame.

Optionally, performing delay alignment processing on the second channel signal of the current frame based on the inter-channel time difference of the previous frame comprises:
To obtain the second channel signal of the current frame after the delay alignment process, the signal of the second process length in the second channel signal of the current frame is changed to the signal of the second alignment process length. stretch,
The second process length is determined based on the inter-channel time difference of the previous frame and the second alignment process length, wherein the second process length is less than the second alignment process length.

Optionally, the second process length is the difference between the second alignment process length and the absolute value of the inter-channel time difference of the previous frame.

Optionally, the starting point of the signal of the second process length is located after the starting point of the signal of the second alignment process length, and the starting point of the signal of the second process length and the starting point of the second alignment process length The length to the start of the signal is the absolute value of the inter-channel time difference of the previous frame.

Optionally, the starting point of the signal of the second alignment process length is located at the starting point of the second channel signal of the current frame or after the starting point of the second channel signal of the current frame and The length between the start point of the alignment process length signal and the end point of the second channel signal of the current frame is greater than or equal to the second alignment process length.

Optionally, a length between the start of the signal of the second alignment process length and the start of the second channel signal of the current frame is equal to the second preset length and the first alignment process length is equal to the sum of the second preset length and the second alignment process length.

L_next_targetは第1のアライメント処理長であり、cur_itdは現在のフレームのチャンネル間時間差であり、prev_itdは前のフレームのチャンネル間時間差であり、Lは遅延アライメント処理の処理長である。 Optionally, the first alignment process length is less than or equal to the frame length of the current frame, and the first alignment process length is a preset length; fill,

L_next_target is the first alignment process length, cur_itd is the inter-channel time difference of the current frame, prev_itd is the inter-channel time difference of the previous frame, and L is the process length of the delayed alignment process.

L_pre_targetは第2のアライメント処理長であり、cur_itdは現在のフレームのチャンネル間時間差であり、prev_itdは前のフレームのチャンネル間時間差であり、Lは遅延アライメント処理の処理長である。 Optionally, the second alignment process length is less than or equal to the frame length of the current frame, and the second alignment process length is a preset length; fill,

L_pre_target is the length of the second alignment process, cur_itd is the inter-channel time difference of the current frame, prev_itd is the inter-channel time difference of the previous frame, and L is the process length of the delayed alignment process.

Lは遅延アライメント処理の処理長であり、MAX_DELAY_CHANGEは隣接するフレームのチャンネル間時間差の間の最大差分値であり、L_initは遅延アライメント処理のプリセット処理長である。 Optionally, the process length of the delayed alignment process is less than or equal to the frame length of the current frame, and the process length of the delayed alignment process is a preset length; fill,

L is the processing length of the delay alignment process, MAX_DELAY_CHANGE is the maximum difference value between the inter-channel time differences of adjacent frames, and L_init is the preset process length of the delay alignment process.

Embodiments of this application provide a stereo signal processing apparatus capable of executing and realizing any stereo signal processing method provided in the above methods.

In a possible design, the stereo signal processing apparatus comprises a plurality of functional modules, eg processing units and transceiver units configured to implement any of the stereo signal processing methods provided above. Therefore, when it is determined that the sign of the inter-channel time difference of the current frame is different from the sign of the inter-channel time difference of the frame before the current frame, the delay alignment process is based on the inter-channel time difference of the current frame. A delay alignment process is performed on the second channel signal of the current frame based on the inter-channel time difference of the previous frame. Therefore, the delay alignment processing of the current frame can be performed based on the actual inter-channel time difference, thereby ensuring a better alignment effect, and the inter-channel time difference of the current frame is forced to zero. , the correlation component between the two channels of the current frame after the delay alignment process cannot be offset, and as a result the energy of the secondary channel signal of the current frame after the time domain downmix increases, resulting in an overall avoiding the prior art problem of affecting the coding quality of

An embodiment of this application provides a stereo signal processing apparatus, the apparatus including a processor and a memory, the memory storing executable instructions, the executable instructions instructing the processor to perform the following steps:
The step of performing delay estimation on the current frame stereo signal to determine the current frame inter-channel time difference, wherein the current frame inter-channel time difference is between the current frame first channel signal and a step, which is the time difference between the current frame and the second channel signal;
For the first channel signal of the current frame based on the inter-channel time difference of the current frame, if the sign of the inter-channel time difference of the current frame is different from the sign of the inter-channel time difference of the frame before the current frame performing delay alignment processing and performing delay alignment processing on the second channel signal of the current frame based on the inter-channel time difference of the previous frame, wherein the first channel signal is the current frame's A target channel signal, a second channel signal, on the same channel as the target channel signal of the previous frame, is used to command the steps to be performed.

Optionally, the executable instructions, when performing delay alignment processing on the first channel signal of the current frame based on the inter-channel time difference of the current frame, instruct the processor to perform the following steps:
The signal of the first processing length in the first channel signal of the current frame is changed to the signal of the first alignment processing length to obtain the first channel signal of the current frame after the delay alignment processing. a step of compressing;
The first process length is determined based on the inter-channel time difference of the current frame and the first alignment process length, wherein the first process length is greater than the first alignment process length, so as to perform the step used to command.

Optionally, the first process length is the sum of the absolute value of the inter-channel time difference of the current frame and the first alignment process length.

Optionally, the starting point of the signal of the first treatment length is located before the starting point of the signal of the first alignment treatment length, such that the starting point of the signal of the first treatment length and the first alignment treatment length is the absolute value of the inter-channel time difference of the current frame.

Optionally, the starting point of the signal of the first alignment process length is located at the starting point of the first channel signal of the current frame or after the starting point of the first channel signal of the current frame, The length between the start point of the alignment process length signal and the end point of the first channel signal of the current frame is greater than or equal to the first alignment process length.

Optionally, the starting point of the signal of the first alignment process length is located before the starting point of the first channel signal of the current frame, and the starting point of the signal of the first alignment process length and the current frame is less than or equal to the transition length, and between the start point of the signal of the first alignment process length and the end point of the first channel signal of the current frame is greater than or equal to the sum of the length of the first alignment process and the transition length, and the transition length is less than or equal to the maximum absolute value of the inter-channel time difference of the current frame.

Optionally, the executable instructions, when performing delay alignment processing on the second channel signal of the current frame based on the inter-channel time difference of the previous frame, instruct the processor to perform the following steps:
To obtain the second channel signal of the current frame after the delay alignment process, the signal of the second process length in the second channel signal of the current frame is changed to the signal of the second alignment process length. a step of stretching,
A second process length is determined based on the inter-channel time difference of the previous frame and a second alignment process length, wherein the second process length is less than the second alignment process length, to perform the step used to command.

Optionally, the second process length is the difference between the second alignment process length and the absolute value of the inter-channel time difference of the previous frame.

Optionally, the starting point of the signal of the second process length is located after the starting point of the signal of the second alignment process length, and the starting point of the signal of the second process length and the starting point of the second alignment process length The length to the start of the signal is the absolute value of the inter-channel time difference of the previous frame.

Optionally, the starting point of the signal of the second alignment process length is located at the starting point of the second channel signal of the current frame or after the starting point of the second channel signal of the current frame and The length between the start point of the alignment process length signal and the end point of the second channel signal of the current frame is greater than or equal to the second alignment process length.

Optionally, a length between the start of the signal of the second alignment process length and the start of the second channel signal of the current frame is equal to the second preset length and the first alignment process length is equal to the sum of the second preset length and the second alignment process length.

L_next_targetは第1のアライメント処理長であり、cur_itdは現在のフレームのチャンネル間時間差であり、prev_itdは前のフレームのチャンネル間時間差であり、Lは遅延アライメント処理の処理長である。 Optionally, the first alignment process length is less than or equal to the frame length of the current frame, and the first alignment process length is a preset length; fill,

L_next_target is the first alignment process length, cur_itd is the inter-channel time difference of the current frame, prev_itd is the inter-channel time difference of the previous frame, and L is the process length of the delayed alignment process.

L_pre_targetは第2のアライメント処理長であり、cur_itdは現在のフレームのチャンネル間時間差であり、prev_itdは前のフレームのチャンネル間時間差であり、Lは遅延アライメント処理の処理長である。 Optionally, the second alignment process length is less than or equal to the frame length of the current frame, and the second alignment process length is a preset length; fill,

L_pre_target is the length of the second alignment process, cur_itd is the inter-channel time difference of the current frame, prev_itd is the inter-channel time difference of the previous frame, and L is the process length of the delayed alignment process.

Lは遅延アライメント処理の処理長であり、MAX_DELAY_CHANGEは隣接するフレームのチャンネル間時間差の間の最大差分値であり、L_initは遅延アライメント処理のプリセット処理長である。 Optionally, the process length of the delayed alignment process is less than or equal to the frame length of the current frame, and the process length of the delayed alignment process is a preset length; fill,

L is the processing length of the delay alignment process, MAX_DELAY_CHANGE is the maximum difference value between the inter-channel time differences of adjacent frames, and L_init is the preset process length of the delay alignment process.

An embodiment of this application provides a stereo signal processing method applied at the decoder side of a stereo codec, the method comprising:
determining the inter-channel time difference of the current frame based on the received codestream, wherein the inter-channel time difference of the current frame is the difference between the first channel signal of the current frame and the second channel signal of the current frame; a step, which is the time difference between
For the first channel signal of the current frame based on the inter-channel time difference of the current frame, if the sign of the inter-channel time difference of the current frame is different from the sign of the inter-channel time difference of the frame before the current frame performing delay recovery processing, performing delay recovery processing on the second channel signal of the current frame based on the inter-channel time difference of the previous frame, wherein the first channel signal is the current frame's A target channel signal, the second channel signal being on the same channel as the target channel signal of the previous frame.

According to the method provided in this application, when it is determined that the sign of the inter-channel time difference of the current frame is different from the sign of the inter-channel time difference of the frame before the current frame, the delay recovery process is The delay recovery process is performed on the first channel signal of the current frame based on the inter-channel time difference of the frame, and the delay recovery process is performed on the second channel signal of the current frame based on the inter-channel time difference of the previous frame. executed. Therefore, the current frame's delay recovery process can be performed based on the actual inter-channel time difference, thereby ensuring a better alignment effect, and the current frame's inter-channel time difference is forced to zero. So the correlation component between the two channels of the current frame after delay recovery processing cannot be offset, and as a result, the energy of the secondary channel signal of the current frame after time domain downmixing increases and the decoding avoiding the prior art problem of affecting signal quality.

Optionally, performing delay recovery processing on the first channel signal of the current frame based on the inter-channel time difference of the current frame comprises:
The signal of the third processing length in the first channel signal of the current frame is combined with the signal of the third alignment processing length to obtain the first channel signal of the current frame after delay recovery processing. stretch,
A third process length is determined based on the inter-channel time difference of the current frame and a third alignment process length, wherein the third process length includes being less than the third alignment process length.

Optionally, the third process length is the difference between the third alignment process length and the absolute value of the inter-channel time difference of the current frame.

Optionally, the starting point of the signal of the third process length is located after the starting point of the signal of the third alignment process length, and the starting point of the signal of the third process length and the starting point of the third alignment process length The length to the start of the signal is the absolute value of the inter-channel time difference of the current frame.

Optionally, the starting point of the signal of the third processing length is located at the starting point of the first channel signal of the current frame or after the starting point of the first channel signal of the current frame and The length between the start point of the signal of the process length and the end point of the first channel signal of the current frame is the difference between the third alignment process length and the absolute value of the inter-channel time difference of the current frame That's it.

Optionally, performing delay recovery processing on the second channel signal of the current frame based on the inter-channel time difference of the previous frame comprises:
The signal of the fourth processing length in the second channel signal of the current frame is combined with the signal of the fourth alignment processing length to obtain the second channel signal of the current frame after delay recovery processing. compress,
A fourth process length is determined based on the inter-channel time difference of the previous frame and a fourth alignment process length, wherein the fourth process length is greater than the fourth alignment process length.

Optionally, the fourth process length is the sum of the absolute value of the inter-channel time difference of the previous frame and the fourth alignment process length.

Optionally, the starting point of the signal of the fourth process length is located before the starting point of the signal of the fourth alignment process length, such that the starting point of the signal of the fourth process length and the fourth alignment process length is the absolute value of the inter-channel time difference of the previous frame.

Optionally, the starting point of the signal of the fourth alignment process length is located at the starting point of the second channel signal of the current frame or after the starting point of the second channel signal of the current frame, The length between the start point of the alignment process length signal and the end point of the second channel signal of the current frame is greater than or equal to the fourth alignment process length.

Optionally, the length between the starting point of the signal of the fourth alignment process length and the starting point of the second channel signal of the current frame is equal to the fourth preset length and the third alignment process length is equal to the sum of the fourth preset length and the fourth alignment process length.

L2_next_targetは第3のアライメント処理長であり、cur_itdは現在のフレームのチャンネル間時間差であり、prev_itdは前のフレームのチャンネル間時間差であり、Lは遅延アライメント処理の処理長である。 Optionally, the third alignment process length is a preset length, or the third alignment process length satisfies the formula:

L2_next_target is the length of the third alignment process, cur_itd is the inter-channel time difference of the current frame, prev_itd is the inter-channel time difference of the previous frame, and L is the process length of the delayed alignment process.

L2_pre_targetは第4のアライメント処理長であり、cur_itdは現在のフレームのチャンネル間時間差であり、prev_itdは前のフレームのチャンネル間時間差であり、Lは遅延アライメント処理の処理長である。 Optionally, the fourth alignment process length is a preset length, or the fourth alignment process length satisfies the formula:

L2_pre_target is the length of the fourth alignment process, cur_itd is the inter-channel time difference of the current frame, prev_itd is the inter-channel time difference of the previous frame, and L is the process length of the delay alignment process.

Lは遅延アライメント処理の処理長であり、MAX_DELAY_CHANGEは隣接するフレームのチャンネル間時間差の間の最大差分値であり、L_initは遅延アライメント処理のプリセット処理長である。 Optionally, the process length of the delayed alignment process is a preset length, or the process length of the delayed alignment process satisfies the formula:

L is the processing length of the delay alignment process, MAX_DELAY_CHANGE is the maximum difference value between the inter-channel time differences of adjacent frames, and L_init is the preset process length of the delay alignment process.

Embodiments of this application provide a stereo signal processing apparatus capable of executing and realizing any stereo signal processing method provided in the above methods.

In a possible design, the stereo signal processing apparatus comprises a plurality of functional modules, eg processing units and transceiver units configured to implement any of the stereo signal processing methods provided above. Therefore, when it is determined that the sign of the inter-channel time difference of the current frame is different from the sign of the inter-channel time difference of the frame previous to the current frame, the delay recovery process determines the current frame time difference based on the inter-channel time difference of the current frame. A delay recovery process is performed on the second channel signal of the current frame based on the inter-channel time difference of the previous frame. Therefore, the current frame's delay recovery process can be performed based on the actual inter-channel time difference, thereby ensuring a better alignment effect, and the current frame's inter-channel time difference is forced to zero. So the correlation component between the two channels of the current frame after delay recovery processing cannot be offset, and as a result, the energy of the secondary channel signal of the current frame after time domain downmixing increases and the decoding avoiding the prior art problem of affecting signal quality.

An embodiment of this application provides a stereo signal processing apparatus, the apparatus including a processor and a memory, the memory storing executable instructions, the executable instructions instructing the processor to perform the following steps:
determining the inter-channel time difference of the current frame based on the received codestream, wherein the inter-channel time difference of the current frame is the difference between the first channel signal of the current frame and the second channel signal of the current frame; a step, which is the time difference between
For the first channel signal of the current frame based on the inter-channel time difference of the current frame, if the sign of the inter-channel time difference of the current frame is different from the sign of the inter-channel time difference of the frame before the current frame performing delay recovery processing, performing delay recovery processing on the second channel signal of the current frame based on the inter-channel time difference of the previous frame, wherein the first channel signal is the current frame's A target channel signal, a second channel signal, on the same channel as the target channel signal of the previous frame, is used to command the steps to be performed.

Optionally, the executable instructions, when performing delay recovery processing on the first channel signal of the current frame based on the inter-channel time difference of the current frame, instruct the processor to perform the following steps:
The signal of the third processing length in the first channel signal of the current frame is combined with the signal of the third alignment processing length to obtain the first channel signal of the current frame after delay recovery processing. a step of stretching,
A third process length is determined based on the inter-channel time difference of the current frame and a third alignment process length, wherein the third process length is less than the third alignment process length, to perform step used to command.

Optionally, the third process length is the difference between the third alignment process length and the absolute value of the inter-channel time difference of the current frame.

Optionally, the starting point of the signal of the third process length is located after the starting point of the signal of the third alignment process length, and the starting point of the signal of the third process length and the starting point of the third alignment process length The length to the start of the signal is the absolute value of the inter-channel time difference of the current frame.

Optionally, the starting point of the signal of the third processing length is located at the starting point of the first channel signal of the current frame or after the starting point of the first channel signal of the current frame and The length between the start point of the signal of the process length and the end point of the first channel signal of the current frame is the difference between the third alignment process length and the absolute value of the inter-channel time difference of the current frame That's it.

Optionally, the executable instructions, when performing delay recovery processing on the second channel signal of the current frame based on the inter-channel time difference of the previous frame, instruct the processor to perform the following steps:
The signal of the fourth processing length in the second channel signal of the current frame is combined with the signal of the fourth alignment processing length to obtain the second channel signal of the current frame after delay recovery processing. a step of compressing;
A fourth process length is determined based on the inter-channel time difference of the previous frame and a fourth alignment process length, wherein the fourth process length is greater than the fourth alignment process length, so as to perform step used to command.

Optionally, the fourth process length is the sum of the absolute value of the inter-channel time difference of the previous frame and the fourth alignment process length.

Embodiments of the present application further provide a computer storage medium that stores a software program and any of the above designs when the software program is read and executed by one or more processors. A stereo signal processing method provided in one may be implemented.

Embodiments of this application further provide a system. The system includes a stereo signal processor provided in any one of the above designs. Optionally, the system may further include other devices interacting with the stereo signal processor in the solutions provided in the embodiments of this application.

An embodiment of this application further provides a computer program product comprising instructions. When the computer program product runs on a computer, the computer performs the methods in the above aspects.

1 is a schematic flowchart of a stereo signal processing method according to an embodiment of this application; 1 is a schematic diagram of a stereo signal processing method according to an embodiment of this application; FIG. 1 is a schematic diagram of a stereo signal processing method according to an embodiment of this application; FIG. 1 is a schematic diagram of a stereo signal processing method according to an embodiment of this application; FIG. 1 is a schematic diagram of a stereo signal processing method according to an embodiment of this application; FIG. 1 is a schematic diagram of a stereo signal processing method according to an embodiment of this application; FIG. 1 is a schematic diagram of a stereo signal processing method according to an embodiment of this application; FIG. 1 is a schematic diagram of a stereo signal processing method according to an embodiment of this application; FIG. 1 is a schematic diagram of a stereo signal processing method according to an embodiment of this application; FIG. 1 is a schematic diagram of a stereo signal processing method according to an embodiment of this application; FIG. 1 is a schematic diagram of a stereo signal processing method according to an embodiment of this application; FIG. 1 is a schematic diagram of a stereo signal processing method according to an embodiment of this application; FIG. 1 is a schematic diagram of a stereo signal processing method according to an embodiment of this application; FIG. 1 is a schematic diagram of a stereo signal processing method according to an embodiment of this application; FIG. 1 is a schematic structural diagram of a stereo signal processing device according to an embodiment of this application; FIG. 1 is a schematic structural diagram of a stereo signal processing device according to an embodiment of this application; FIG. 1 is a schematic structural diagram of a stereo signal processing device according to an embodiment of this application; FIG. 1 is a schematic structural diagram of a stereo signal processing device according to an embodiment of this application; FIG.

Below, this application is further described in detail with reference to the accompanying drawings.

Embodiments of this application are applicable to the encoding and decoding of audio signals, in particular stereo signals. Currently, stereo signal coding mainly consists of the following processes: time domain preprocessing, delay estimation and encoding, delay alignment, time domain analysis, downmix parameter extraction and encoding, time domain downmix processing, down Including mixed signal coding. The audio signal decoding process may be the opposite of the audio signal encoding process, and the details are not described here.

The encoding process is only an example and the actual encoding process may vary. This is not a limitation in the embodiments of this application. In the embodiments of this application, delay alignment is primarily dealt with. Delay alignment is described in detail below. In addition, reference is made to the description in the prior art for other steps of the encoding process. The details will not be described here one by one.

In the embodiments of this application, each frame of the stereo signal includes a left channel signal and a right channel signal, and has a frame length of N, where N is a positive integer greater than zero.

FIG. 1 is a schematic flowchart of a stereo signal processing method according to an embodiment of this application.

Referring to FIG. 1, the method includes the following steps.

Step 101: Perform delay estimation on the stereo signal of the current frame to determine the inter-channel time difference of the current frame, and the inter-channel time difference of the current frame is the first channel signal of the current frame. is the time difference between the second channel signal of the current frame.

Step 102: If the sign of the inter-channel time difference of the current frame is different from the sign of the inter-channel time difference of the previous frame of the current frame, the first channel signal of the current frame is based on the inter-channel time difference of the current frame. perform delay alignment processing on the second channel signal of the current frame based on the inter-channel time difference of the previous frame, and perform delay alignment processing on the first channel signal of the current frame A target channel signal, the second channel signal is on the same channel as the target channel signal of the previous frame.

The frame before the current frame and the current frame are two adjacent frames and are consecutive in time sequence.

In step 101, the process of performing delay estimation for the current frame may be as follows.

Step 1: Perform time-domain preprocessing on the left and right channel signals of the current frame.

If the sampling rate of the stereo signal is 16KHz, the duration of one frame of the stereo signal is 20ms, the frame length is noted as N, N=320, that is, the frame length is 320 sampling points. be. The current frame stereo signal includes the current frame left channel signal and the current frame right channel signal, where the current frame left channel signal is denoted as x L (n) and the current frame right channel signal is denoted as x _L (n). The channel signal is denoted as x _R (n), where n is the sampling point sequence number and n=0,1,...,N-1.

b₀=0.994461788958195であり、b₁=-1.988923577916390であり、b₂=0.994461788958195であり、a₁=1.988892905899653であり、a₂=-0.988954249933127であり、zはZ変換の変換ファクタである。対応して、時間領域フィルタリングの後に取得される信号は、

である。 Performing time-domain preprocessing on the left channel signal and the right channel signal of the current frame is to obtain a preprocessed left channel signal and a preprocessed right channel signal of the current frame. , the preprocessed left channel signal of the current frame is denoted as x L_HP (n), and the processed right channel signal of the current frame is denoted as x _{L_HP} (n). The channel signal is denoted as x _{R_HP} (n), where n is the sampling point sequence number, specifically including n=0,1,...,N-1. The high-pass filtering process may be an Infinite Impulse Response (IIR) filter with a cutoff frequency of 20 Hz, or may be performed by other types of filters. For example, the transfer function of a high-pass filter with a sampling rate of 16KHz and a corresponding cutoff frequency of 20Hz is:

b ₀ =0.994461788958195, b ₁ =-1.988923577916390, b ₂ =0.994461788958195, a ₁ =1.988892905899653, a ₂ =-0.988954249933127, z is the transform factor for the Z transform. Correspondingly, the signal obtained after time domain filtering is

is.

It should be noted that time domain pre-processing for the left and right channel signals of the current frame is not mandatory. If there is no time-domain preprocessing step, the left and right channel signals used for delay estimation and delay alignment processing are the left and right channel signals in the original stereo signal. Here, the left and right channel signals in the original stereo signal are the collected Pulse Code Modulation (PCM) signals obtained after Analog to Digital (A/D) conversion. is. Further, in this embodiment of this application, the sampling rate of the signal may also be 8 KHz, 16 KHz, 32 KHz, 44.1 KHz, 48 KHz, and so on. This is not a limitation in this embodiment of this application.

として記され、現在のフレームの前処理された右チャンネル信号は、

として記され、nはサンプリング点シーケンス番号であり、n=0,1,...,N-1である。 The preprocessed left channel signal of the current frame is

, and the preprocessed right channel signal of the current frame is

where n is the sampling point sequence number, n=0,1,...,N-1.

Further, the pre-processing may be other processing schemes such as pre-emphasis processing in addition to the high-pass filtering processing described in this embodiment of this application. This is not a limitation in this embodiment of this application.

Step 2: Perform delay estimation based on the preprocessed left channel signal and the preprocessed right channel signal of the current frame to obtain the inter-channel time difference of the current frame.

For example, the cross-correlation coefficient between left and right channels may be calculated based on the preprocessed left channel signal and the preprocessed right channel signal of the current frame. A maximum value of the cross-correlation coefficient is then determined, and an inter-channel time difference for the current frame is determined based on the maximum value of the cross-correlation coefficient.

Specifically, T _max corresponds to the maximum inter-channel time difference at the current sampling rate, and T _min corresponds to the minimum inter-channel time difference at the current sampling rate. _Tmax and _Tmin are preset real numbers and _Tmax is greater than _Tmin . In this embodiment of this application, T _max =40 and T _min =−40 when the sampling rate is 16 KHz. When the sampling rate is 32 KHz, T _max =80 and T _min =-80. For other sampling rates the values of _Tmax and _Tmin are not further stated.

A cross-correlation coefficient between the left and right channels may be calculated in the following manner.

When T _min is less than or equal to 0 and T _max is greater than 0, the cross-correlation coefficient between the left and right channels satisfies the following formula within T _min ≤ i ≤ 0.

Nはフレーム長であり、

は現在のフレームの前処理された左チャンネル信号であり、

は現在のフレームの前処理された右チャンネル信号であり、c(i)は左チャンネルと右チャンネルとの間の相互相関係数であり、iは相互相関係数のインデックス値である。 Within 0 < i ≤ T _max , the cross-correlation coefficient between the left and right channels satisfies the following equation,

N is the frame length,

is the preprocessed left channel signal of the current frame, and

is the preprocessed right channel signal of the current frame, c(i) is the cross-correlation coefficient between left and right channels, and i is the index value of the cross-correlation coefficient.

Nはフレーム長であり、

は現在のフレームの前処理された左チャンネル信号であり、

は現在のフレームの前処理された右チャンネル信号であり、c(i)は左チャンネルと右チャンネルとの間の相互相関係数であり、iは相互相関係数のインデックス値である。 When _Tmin is less than or equal to 0 _{and Tmax} is less than or equal to ₀ , within the range of _{Tmin≤i≤Tmax} , the cross-correlation coefficient between the left channel and the right channel satisfies the following formula,

N is the frame length,

is the preprocessed left channel signal of the current frame, and

is the preprocessed right channel signal of the current frame, c(i) is the cross-correlation coefficient between left and right channels, and i is the index value of the cross-correlation coefficient.

Nはフレーム長であり、

は現在のフレームの前処理された左チャンネル信号であり、

は現在のフレームの前処理された右チャンネル信号であり、c(i)は左チャンネルと右チャンネルとの間の相互相関係数であり、iは相互相関係数のインデックス値である。 When the set T _min is greater than 0 and the set T _max is greater than 0, within the range T _min < i ≤ T _max , the cross-correlation coefficient between the left and right channels is satisfies the formula of

N is the frame length,

is the preprocessed left channel signal of the current frame, and

is the preprocessed right channel signal of the current frame, c(i) is the cross-correlation coefficient between left and right channels, and i is the index value of the cross-correlation coefficient.

Finally, the index value corresponding to the maximum obtained value of the cross-correlation coefficient is used as the inter-channel time difference of the current frame.

With reference to the discussion above, in this embodiment of this application, when T _max equals 40 and T _min equals −40, the cross-correlation coefficient c(i) between the left and right channels is The maximum value is searched within T _min ≤ i ≤ T _max and the index value corresponding to the obtained maximum value of the cross-correlation coefficient is used as the inter-channel time difference for the current frame, which is noted as cur_itd. be done.

After the current frame's inter-channel time difference is estimated, quantization and encoding are performed on the current frame's estimated inter-channel time difference, the quantized code indices are written to the code stream, and the code A stream is sent to the decoder side. Optionally, the quantized and encoded value is used as the inter-channel time difference for the current frame.

In addition to the delay estimation methods described above, the inter-channel time difference of the current frame may alternatively be determined according to other delay estimation methods. For example, the cross-correlation coefficient between the left channel and the right channel is based on the preprocessed left channel signal and the preprocessed right channel signal of the current frame or the left channel signal and the right channel signal of the current frame. calculated by Then, a long-term smoothing process is performed on the first M1 audio frames (M1 is an integer greater than or equal to 1) to obtain a smoothed cross-correlation coefficient between the left and right channels. and the calculated cross-correlation coefficient between the left and right channels of the current frame. Then, the maximum value of the smoothed cross-correlation coefficient between the left channel and the right channel is searched within the range of T _min ≤ i ≤ T _max , the index value corresponding to the maximum value is obtained, and now is used as the channel-to-channel time difference between frames. In another example, the inter-frame smoothing process alternatively combines the inter-channel time difference of the first M2 audio frames (where M2 is an integer greater than or equal to 1) and the estimated inter-channel time difference of the current frame. and the smoothed inter-channel time difference is used as the inter-channel time difference of the current frame.

In this embodiment of this application, the estimated inter-channel time difference of the current frame is used as the final determined inter-channel time difference of the current frame, whereas in order to estimate the inter-channel time difference of the current frame It should be noted that the methods of include, but are not limited to, the methods described above.

In step 102, the sign may indicate a plus sign (+) or a minus sign (-). In this embodiment of this application, the previous frame is located before and adjacent to the current frame.

When it is determined that the sign of the inter-channel time difference of the current frame is different from the sign of the inter-channel time difference of the previous frame, the delay alignment process is applied to the first channel signal and the second channel signal of the current frame. may be run separately. For ease of explanation, hereinafter the channel corresponding to the first channel signal of the current frame will be referred to as the first channel, and the channel corresponding to the second channel signal of the current frame will be referred to as the second channel. called a channel. The first channel is the target channel of the current frame, and may also be called the target channel of the next frame, or the designated target channel of the current frame, or the target channel of the current frame. It should be noted that other channels than the target channel of the frame before the frame may be called. Correspondingly, the second channel is the reference channel of the current frame, the second channel is the channel within the two channels of the stereo signal and the same as the target channel of the previous frame, and , may be called the target channel of the previous frame, or may be called the designated reference channel of the current frame, or may be called a channel other than the target channel of the current frame. For example, if the target channel in the previous frame is the left channel, the first channel signal is the right channel signal in the current frame and the second channel signal is the left channel signal in the current frame. If the target channel in the previous frame is the right channel, the first channel signal is the left channel signal in the current frame and the second channel signal is the right channel signal in the current frame.

In this embodiment of this application, target channel and reference channel are terms of art. Specifically, existing algorithms for performing delay alignment based on inter-channel time difference require that one channel be selected from the left and right channels, and the delay alignment process Executed on the signal. This channel is called the target channel. The other channel is used as a reference for performing delay alignment processing on the target channel and is called the reference channel. In the method proposed in this embodiment of this application, when it is determined that the sign of the inter-channel time difference of the current frame is different from the sign of the inter-channel time difference of the previous frame, the delay alignment process is applied to both channels. must be executed. Therefore, when it is determined that the sign of the inter-channel time difference of the current frame is different from the sign of the inter-channel time difference of the previous frame, the first channel is the target channel of the current frame in the broad sense, and the delay alignment process but needs to be performed against the target channel of the current frame, the second channel is the reference channel of the current frame in the broad sense, and the delay alignment process is also performed against the reference channel of the current frame need to be executed.

Optionally, in this embodiment of this application, the target and reference channels of the previous frame may be determined in the following manner to determine the first and second channels. If the inter-channel time difference of the previous frame is less than 0, it may be considered that the target channel of the previous frame is the left channel. The second channel is the same channel as the target channel of the previous frame in the two channels of the stereo signal, so the second channel is the left channel and the first channel is the right channel. If the inter-channel time difference of the previous frame is greater than or equal to 0, it may be considered that the target channel of the previous frame is the right channel. The second channel is the same channel as the target channel of the previous frame in the two channels of the stereo signal, so the second channel is the right channel and the first channel is the left channel.

Optionally, in this embodiment of this application, the target channel and reference channel of the current frame may alternatively be determined in the following manner to determine the first and second channels . When the inter-channel time difference of the current frame is determined to be greater than or equal to 0, the target channel of the current frame is the right channel, i.e. the first channel is the right channel and the second channel is the left channel. It may be considered that there is. When the inter-channel time difference of the current frame is determined to be less than 0, the target channel of the current frame is the left channel, i.e. the first channel is the left channel and the second channel is the right channel. It may be considered that there is.

Optionally, in this embodiment of this application, the target channel and reference channel of the previous frame are the obtained target channel index or reference of the previous frame to determine the first channel and the second channel. It may be determined directly based on the channel index.

In this embodiment of this application, there are multiple methods for performing delay alignment processing on the first channel signal and the second channel signal, which are described separately below.

1. Perform delay alignment processing on the first channel signal of the current frame based on the inter-channel time difference of the current frame.

Specifically, the signal of the first processing length in the first channel signal of the current frame is subjected to the first alignment to obtain the first channel signal of the current frame after delay alignment processing. Compressed to process length signal. The first process length is determined based on the inter-channel time difference of the current frame and the first alignment process length, where the first process length is greater than the first alignment process length.

In this embodiment of this application, the first process length may be the sum of the absolute value of the inter-channel time difference of the current frame and the first alignment process length.

In this embodiment of this application, the first alignment length may be represented by L_next_target. The first alignment process length is less than or equal to the frame length of the current frame, and the first alignment process length may be a preset length or determined in some other manner. When the first alignment process length is the preset length, the first alignment process length may be L, L/2, L/3, or any length less than or equal to L, where L is the length of the delayed alignment process is long. The processing length of the delay alignment process is less than or equal to the frame length of the current frame, i.e., L is any value less than or equal to the corresponding frame length N at the current sampling rate and greater than the maximum absolute value of the inter-channel time difference. is some preset positive integer. For example, L=290 or L=200. In this embodiment of this application, L may be set to different values for different sampling rates, or may be a uniform value. In general, the values may be preset based on the experience of those skilled in the art. For example, L is set to 290 when the sampling rate is 16KHz. In this case, L_next_target=L/2=145 in this embodiment of this application.

Further, in this embodiment of this application, the starting point of the signal of the first treatment length is located before the starting point of the signal of the first alignment treatment length and is aligned with the starting point of the signal of the first treatment length. The length between the starting point of the signal of the first alignment process length is the absolute value of the inter-channel time difference of the current frame.

In this embodiment of this application, the inter-channel time difference of the current frame is cur_itd, and abs(cur_itd) represents the absolute value of the inter-channel time difference of the current frame. For ease of explanation, abs(cur_itd) will be referred to as the first delay length in the following discussion. The inter-channel time difference of the previous frame is prev_itd, and abs(prev_itd) represents the absolute value of the inter-channel time difference of the previous frame. For ease of explanation, abs(prev_itd) is referred to as the second delay length in the following discussion.

The specific position of the signal of the first processing length may be determined based on different actual conditions, which are described separately below.

First possible case:

FIG. 2 is a schematic diagram of a delay alignment process according to embodiments of this application. In FIG. 2, for ease of explanation, the point in the first channel signal before the delay alignment process and the point in the first channel signal after the compression process at the same position have the same coordinates. This does not mean that the signals of points with the same coordinates are the same. For example, both coordinates of the starting point of the first channel signal of the current frame are marked as B1 before the delay alignment process and after the compression process.

Referring to FIG. 2, the starting point of the signal of the first alignment process length is located at the starting point B1 of the first channel signal of the current frame. The end point of the signal of the first alignment process length is C1, the length from the start point B1 to the end point C1 is equal to the first alignment process length, B1=0, C1=B1+L_next_target- 1.

The starting point A1 of the signal of the first processing length is positioned before the starting point B1 of the signal of the first alignment processing length, and the starting point A1 of the signal of the first processing length and the starting point A1 of the signal of the first alignment processing length The length between the start point B1 of the signal is the absolute value of the inter-channel time difference of the current frame. That is, A1=B1-abs(cur_itd). The end point of the signal of the first process length is C1, which is the same coordinate as the end point of the signal of the first alignment process length.

In the process of delay alignment processing, signals from point A1 to point C1 in the first channel signal are compressed into signals of the first alignment processing length, and the compressed signals of the first alignment processing length are compressed into It is used as the signal of the first alignment process length starting from the starting point B1 in the later first channel signal. Furthermore, the uncompressed signal in the first channel signal of the current frame remains unchanged, i.e. the signal from point C1+1 to point E1 in the first channel signal before the delay alignment process is It is used directly as the signal from point C1+1 to point E1 in the first channel signal after compression processing. E1 is the end point of the first channel signal of the current frame, the frame length of the current frame is N, and E1=N-1.

In this embodiment of this application, the first delay length signal is manually reconstructed based on the signal from point E2-abs(cur_itd)+1 to point E2 in the second channel signal of the current frame. and the reconstructed signal of the first delay length is used as the signal from point E1+1 to point G1 in the first channel signal after compression processing, and E2 is the current frame's The end point of the second channel signal, E2=E1 and G1=E1+abs(cur_itd).

It should be noted that how the signal of the first delay length is specifically reconstructed is not limited in this embodiment of this application. For example, the signal from point E1-abs(cur_itd)+1 to point E1 in the second channel signal of the current frame may be directly used as the reconstructed signal of the first delay length.

Finally, in the first channel signal after compression processing, N sampling points starting from point F1 are used as the first channel signal of the current frame after delay alignment processing. That is, the starting point of the first channel signal of the current frame after delay alignment processing is point F1 and the ending point is G1. The point F1 is located after the starting point of the first channel signal of the current frame, and the length between the point F1 and the starting point of the first channel signal of the current frame is the first delay length be. The point G1 is located after the end point of the first channel signal of the current frame, and the length between the point G1 and the end point of the first channel signal of the current frame is the first delay length be. That is, F1=B1+abs(cur_itd).

For example, referring to FIG. 2, if the first channel of the current frame is the left channel and the second channel is the right channel, then the signal from point A1 to point C1 on the left channel is the first The compressed signal of the first alignment length is compressed to the signal of the alignment length, and the compressed signal of the first alignment length is the signal of the first alignment length within the left channel signal after compression (i.e., the left channel signal after compression). signal from point B1 to point C1). The signal from point C1+1 to point E1 in the left channel signal before compression is then directly used as the signal from point C1+1 to point E1 in the left channel signal of the current frame after compression. used. Then, the signal of the first delay length is the signal of the first delay length before the end point in the right channel signal of the current frame (i.e., the point E1-abs(cur_itd )+1 to point E1), the reconstructed signal of the first delay length is the first delay length after the end point in the left channel signal after compression processing. (ie, signals from point E1+1 to point G1 in the left channel signal after compression processing). Finally, the signal from point F1 to point G1 in the signal obtained after compression processing is used as the left channel signal of the current frame after delay alignment processing.

If the first channel of the current frame is the right channel and the second channel is the left channel, refer to the above description. Details are not described here.

Second possible case:

FIG. 3 is a schematic diagram of stereo signal processing according to an embodiment of this application. In FIG. 3, for ease of explanation, a point in the first channel signal before the delay alignment process and a point in the first channel signal after the compression process at the same position have the same coordinates. This does not mean that the signals of points with the same coordinates are the same. For example, both coordinates of the starting point of the first channel signal of the current frame are marked as B1 before the delay alignment process and after the compression process.

Referring to FIG. 3, the starting point D1 of the first alignment length signal is located after the starting point B1 of the first channel signal of the current frame, and the starting point D1 of the first alignment length signal is located after the starting point B1 of the first channel signal in the current frame. and the end point E1 of the first channel signal of the current frame is greater than or equal to the first alignment processing length. The end point of the signal of the first alignment process length is C1, and the length from the start point D1 to the end point C1 is equal to the first alignment process length, C1=D1+L_next_target-1.

In FIG. 3, the frame length of the current frame is N, the starting point of the first channel signal of the current frame is B1=0, and the ending point of the first channel signal of the current frame is E1=N. -1. The starting point D1 of the first alignment process length is located after the starting point B1 of the first channel signal of the current frame, and the starting point D1 of the signal of the first alignment process length and the first channel signal of the current frame The length between the end point E1 of the channel signal is longer than or equal to the first alignment processing length. For ease of explanation, the length between the starting point D1 of the signal of the first alignment process length and the starting point B1 of the first channel signal is hereinafter referred to as the first preset length. The first preset length is greater than 0 and less than or equal to the difference value between the frame length of the current frame and the first alignment processing length, and may be specifically set according to the actual situation. Details are not described here.

The starting point A1 of the signal of the first processing length is located before the starting point D1 of the signal of the first alignment processing length, and the starting point A1 of the signal of the first processing length and the starting point A1 of the signal of the first alignment processing length are located before the starting point D1 of the signal of the first alignment processing length. The length between the start point D1 of the signal is the absolute value of the inter-channel time difference of the current frame. That is, the starting point of the signal of the first treatment length is A1=D1-abs(cur_itd), the ending point of the signal of the first treatment length is C1, which is the signal of the first alignment treatment length is the same as the coordinates of the end point of

In this embodiment of this application, in the process of delay alignment processing, during signal compression, a first preset length of a first preset length that is within the first channel signal and is located before the start of the signal of the first processing length. The signal may be used directly as a first preset length signal starting from the starting point of the first channel signal after compression processing. That is, the signal from point H1 to point A1-1 in the first channel signal is used as the signal from point B1 to point D1-1 in the compressed first channel signal, H1=B1-abs (cur_itd).

In the signal compression process, the signal from point A1 to point C1 in the first channel signal is compressed into a signal of the first alignment process length, and the compressed signal of the first alignment process length is the signal after the compression process. It is used as the first alignment length signal starting from point D1 in the first channel signal. That is, the compressed signal of the first alignment processing length is directly used as the signal from point D1 to point C1 in the first channel signal after compression processing.

Furthermore, the uncompressed signal in the first channel signal of the current frame remains unchanged, i.e. from point C1+1 to point E1 in the first channel signal of the current frame before delay alignment processing. is directly used as the signal from point C1+1 to point E1 in the first channel signal after compression processing. E1 is the end point of the first channel signal of the current frame, the frame length of the current frame is N, and E1=N-1.

In this embodiment of this application, the first delay length signal is manually reconstructed based on the signal from point E2-abs(cur_itd)+1 to point E2 in the second channel signal of the current frame. and the reconstructed signal of the first delay length is used as the signal from point E1+1 to point G1 in the first channel signal after compression processing, and E2 is the current frame's The end point of the second channel signal, E2=E1 and G1=E1+abs(cur_itd).

It should be noted that how the signal of the first delay length is specifically reconstructed is not limited in this embodiment of this application. For example, the signal from point E2-abs(cur_itd)+1 to point E2 in the second channel signal of the current frame may be directly used as the reconstructed signal of the first delay length.

Finally, in the first channel signal after compression processing, N sampling points starting from point F1 are used as the first channel signal of the current frame after delay alignment processing. That is, the starting point of the first channel signal of the current frame after delay alignment processing is point F1, the ending point is G1, F1=B1+abs(cur_itd), G1=E1+abs(cur_itd ).

For example, referring to FIG. 3, the first channel of the current frame is the left channel and the second channel is the right channel. The signals from point H1 to point A1-1 in the left channel signal are directly used as the signals from point B1 to point D1-1 in the left channel signal after compression processing. The signal from point A1 to point C1 in the left channel signal is compressed to the signal of the first alignment process length, and the compressed signal of the first alignment process length is the signal from point D1 in the left channel signal after the compression process. to point C1. Then the signal from point C1+1 to point E1 in the left channel signal of the current frame is directly used as the signal from point C1+1 to point E1 in the left channel signal after compression processing. Then the signal of the first delay length is manually reconstructed based on the signal from point E2-abs(cur_itd)+1 to point E2 in the right channel signal of the current frame, and the signal of the first delay length is The reconstructed signal is used as the signal from point E1+1 to point G1 in the left channel signal after compression processing. Finally, the signal from point F1 to point G1 in the signal obtained after compression processing is used as the left channel signal of the current frame after delay alignment processing.

If the first channel of the current frame is the right channel and the second channel is the left channel, refer to the above description. Details are not described here.

Third possible case:

FIG. 4 is a schematic diagram of stereo signal processing according to an embodiment of this application. In FIG. 4, for ease of explanation, a point in the first channel signal before the delay alignment process and a point in the first channel signal after the compression process at the same position have the same coordinates. This does not mean that the signals of points with the same coordinates are the same. For example, both coordinates of the end point of the first channel signal of the current frame are marked as E1 before the delay alignment process and after the compression process.

In FIG. 4, the frame length of the current frame is N, the starting point of the first channel signal of the current frame is B1=0, and the ending point of the first channel signal of the current frame is E1=N. -1. The starting point D1 of the first alignment process length is located before the starting point B1 of the first channel signal of the current frame, and the starting point D1 of the signal of the first alignment process length and the first channel signal of the current frame The length between the starting point B1 of the channel signal of the current frame is less than or equal to the transition length, and the length between the starting point D1 of the signal of the first alignment process length and the ending point E1 of the first channel signal of the current frame The length of is greater than or equal to the sum of the first alignment process length and the transition length. For ease of explanation, in this embodiment of this application and in FIG. 4, the transition interval length is denoted by ts. In this case D1=B1-ts. The end point of the signal of the first alignment process length is C1, and the length from the start point D1 to the end point C1 is equal to the first alignment process length, C1=D1+L_next_target-1.

In this embodiment of this application, the transition interval length may be a preset positive integer, and the preset positive integer may be set based on experience by those skilled in the art. The transition interval length is typically less than or equal to the maximum absolute value of the inter-channel time difference of the current frame. The transition interval length may alternatively be calculated based on the inter-channel time difference of the current frame. For example, the transition interval length is abs(cur_itd)/2.

The starting point A1 of the signal of the first processing length is located before the starting point D1 of the signal of the first alignment processing length, and the starting point A1 of the signal of the first processing length and the starting point A1 of the signal of the first alignment processing length are located before the starting point D1 of the signal of the first alignment processing length. The length between the start point D1 of the signal is the absolute value of the inter-channel time difference of the current frame. That is, the starting point of the signal of the first treatment length is A1=D1-abs(cur_itd), the ending point of the signal of the first treatment length is C1, which is the signal of the first alignment treatment length is the same as the coordinates of the end point of

In FIG. 4, it is an illustrative example that the length between the starting point D1 of the signal of the first alignment process length and the starting point B1 of the first channel signal of the current frame is equal to the transition length. Note that it is used as The length between the starting point D1 of the signal of the first alignment process length and the starting point B1 of the first channel signal of the current frame may alternatively be less than the transition length, D1<B1, and D1 >B1. For the case of less than the transition length, see the description here. No further details are given.

In the process of delay alignment processing, signals from point A1 to point C1 in the first channel signal are compressed into signals of the first alignment processing length, and the compressed signals of the first alignment processing length are compressed into It is used as the signal of the first alignment process length starting from point D1 in the later first channel signal. That is, the compressed signal of the first alignment processing length is used as the signal from point D1 to point C1 in the first channel signal after compression processing.

Furthermore, the uncompressed signal in the first channel signal of the current frame remains unchanged, i.e. from point C1+1 to point E1 in the first channel signal of the current frame before delay alignment processing. is directly used as the signal from point C1+1 to point E1 in the first channel signal after compression processing. E1 is the end point of the first channel signal of the current frame, the frame length of the current frame is N, and E1=N-1.

In this embodiment of this application, the first delay length signal is manually reconstructed based on the signal from point E2-abs(cur_itd)+1 to point E2 in the second channel signal of the current frame. and the reconstructed signal of the first delay length is used as the signal from point E1+1 to point G1 in the first channel signal after compression processing, and E2 is the current frame's The end point of the second channel signal, E2=E1 and G1=E1+abs(cur_itd).

It should be noted that how the signal of the first delay length is specifically reconstructed is not limited in this embodiment of this application.

Finally, in the first channel signal after compression processing, N sampling points starting from point F1 are used as the first channel signal of the current frame after delay alignment processing. That is, the starting point of the first channel signal of the current frame after delay alignment processing is point F1, the ending point is G1, and F1=B1+abs(cur_itd).

For example, referring to FIG. 4, the first channel of the current frame is the left channel and the second channel is the right channel. The signal from point A1 to point C1 in the left channel signal is compressed to the signal of the first alignment process length, and the compressed signal of the first alignment process length is the signal from point D1 in the left channel signal after the compression process. to point C1. Then the signal from point C1+1 to point E1 in the left channel signal of the current frame is directly used as the signal from point C1+1 to point E1 in the left channel signal after compression processing. Then the signal of the first delay length is manually reconstructed based on the signal from point E2-abs(cur_itd)+1 to point E2 in the right channel signal of the current frame, and the signal of the first delay length is The reconstructed signal is used as the signal from point E1+1 to point G1 in the left channel signal after compression processing. E2 is the end point of the right channel signal of the current frame. Finally, the signal from point F1 to point G1 in the signal obtained after compression processing is used as the left channel signal of the current frame after delay alignment processing.

If the first channel of the current frame is the right channel and the second channel is the left channel, refer to the above description. Details are not described here.

Optionally, a smoothed transition interval may also be set to add smoothing between the actual signal and the manually reconstructed signal, the length of the smoothed transition interval being Ts2. . The length of the smoothed transition interval may be set to a preset positive integer, and the difference between the length of the smoothed transition interval and the transition interval length is the difference between the frame length and the first alignment process length It is below. For example, Ts2 is set to 10.

In this case, in the process of delay alignment processing, the signal from point A1 to point C1 in the first channel signal is compressed into a signal of the first alignment processing length, and the compressed signal of the first alignment processing length is It is used as the signal of the first alignment process length starting from the point D1 in the first channel signal after the compression process. That is, the compressed signal of the first alignment processing length is used as the signal from point D1 to point C1 in the first channel signal after compression processing.

Furthermore, the signal from point C1+1 to point E1-Ts2 in the first channel signal of the current frame before delay alignment processing is equal to point C1+1 in the first channel signal after compression processing. Used directly as a signal up to points E1-Ts2. E1 is the end point of the first channel signal of the current frame, the frame length of the current frame is N, and E1=N-1. The smoothed transition interval length signal is manually reproduced based on the signal from point E2-abs(cur_itd)-Ts2+1 to point E2-abs(cur_itd) in the second channel signal of the current frame. The reconstructed signal of the length of the smoothed transition interval is used as the signal from point E1-Ts2+1 to point E1 of the first channel signal after compression processing.

In this embodiment of this application, the first delay length signal is manually reconstructed based on the signal from point E2-abs(cur_itd)+1 to point E2 in the second channel signal of the current frame. and the reconstructed signal of the first delay length is used as the signal from point E1+1 to point G1 in the first channel signal after compression processing, and E2 is the current frame's The end point of the second channel signal, E2=E1 and G1=E1+abs(cur_itd).

It should be noted that how the first delay length signal and the smoothed transition interval length signal are specifically reconstructed is not limited in this embodiment of the application.

Note that in the second possible case the transition interval length may also be set. The specific method and steps for setting the transition interval length and the process of performing delay alignment processing on the first channel signal of the current frame after the transition interval length is set are described above. See Details are not described here. In a second possible case, the transition interval length and the smoothed transition interval length may also be set. A specific method and steps for setting the transition interval length and the smoothed transition interval length, and the first channel signal of the current frame after the transition interval length and the smoothed transition interval length are set See the discussion above for the process of performing delayed alignment operations on .

In the above methods, the smoothing between frames is added by adding the transition interval length, or by adding the transition interval length and the smoothed transition interval length, and the current frame after the delay alignment process. The accuracy of alignment between the two channel signals within is improved and the coding quality is improved.

In this embodiment of this application, the method for compressing the signal of the first processing length may be compressing the signal by using a cubic spline interpolation method, quadratic spline interpolation The signal may be compressed by using a method, the signal may be compressed by using a linear interpolation method, or a B-spline interpolation such as a quadratic B-spline interpolation method or a cubic B-spline interpolation method. It should be noted that the signal may also be compressed by using the method. The specific compression method is not limited in this embodiment of this application and compression may be handled using either technique.

2. Perform delay alignment processing on the second channel signal of the current frame based on the inter-channel time difference of the previous frame.

Specifically, the signal of the second processing length in the second channel signal is the signal of the second alignment processing length to obtain the second channel signal of the current frame after the delay alignment processing. is stretched to A second process length is determined based on the inter-channel time difference of the previous frame and a second alignment process length, where the second process length is less than the second alignment process length.

In this embodiment of this application, the second process length is the difference between the second alignment process length and the absolute value of the inter-channel time difference of the previous frame. In embodiments of this application, the second alignment process length may be represented by L_pre_target.

The second alignment process length may be a preset length or determined in some other manner. The second alignment process length is less than or equal to the frame length of the current frame. When the second alignment process length is the preset length, the second alignment process length may be L, L/2, L/3, or any length less than or equal to L. L is any preset positive integer less than or equal to the corresponding frame length N at the current sampling rate and greater than the maximum absolute value of the inter-channel time difference. For example, L=290 or L=200. In this embodiment of this application, L may be set to different values for different sampling rates, or may be a uniform value. In general, the values may be preset based on the experience of those skilled in the art. For example, L is set to 290 when the sampling rate is 16KHz. In this embodiment of this application, L_pre_target=L/2=145.

Further, the starting point of the signal of the second process length is located after the starting point of the signal of the second alignment process length, and the starting point of the signal of the second process length and the signal of the second alignment process length The length to the start point is the absolute value of the inter-channel time difference of the previous frame.

The specific position of the signal of the second processing length may be determined based on different actual conditions, which are described separately below.

First possible case:

FIG. 5 is a schematic diagram of stereo signal processing according to an embodiment of this application. In FIG. 5, for ease of explanation, a point in the second channel signal before the delay alignment process and a point in the second channel signal after the decompression process at the same position have the same coordinates. This does not mean that the signals of points with the same coordinates are the same. For example, both coordinates of the starting point of the second channel signal of the current frame are marked as B2 before the delay alignment process and after the compression process.

Referring to FIG. 5, the frame length of the current frame is N, the start point of the second channel signal of the current frame is B2=0, and the end point of the second channel signal of the current frame is E2 =N-1. The starting point of the second alignment process length is located at the starting point B2 of the second channel signal of the current frame. The end point of the signal of the second alignment process length is C2, and the length from the start point B2 to the end point C2 is equal to the second alignment process length, C2=B2+L_pre_target-1.

The starting point A2 of the signal of the second process length is located after the starting point B2 of the second alignment process length, and the starting point A2 of the signal of the second process length and the starting point B2 of the second alignment process length is the absolute value of the inter-channel time difference of the previous frame. The start point of the signal of the second treatment length is A2=B2+abs(prev_itd) and the end point of the signal of the second treatment length is C2, which is the same as the signal of the second alignment treatment length. Same as the coordinates of the end point.

In the process of delayed alignment processing, the signal from point A2 to point C2 in the second channel signal is stretched to the signal of the second alignment length, and the stretched signal of the second alignment length is subjected to the stretch processing. It is used as the signal of the second alignment process length starting from point B2 in the later second channel signal. That is, the decompressed signal of the second alignment processing length is used as the signal from the starting point B2 to the point C2 in the second channel signal after decompression processing.

In this embodiment of this application, the unexpanded signal of the second channel signal of the current frame may remain unchanged during signal expansion, i.e. the point C2+1 in the second channel signal of the current frame to point E2 is directly used as the signal from point C2+1 to point E2 in the second channel signal after decompression. E2 is the end point of the second channel signal of the current frame, the frame length of the current frame is N, and E2=N-1.

Finally, in the second channel signal after decompression process, the N sampling points starting from the starting point B2 are used as the second channel signal of the current frame after delay alignment process. That is, the starting point of the second channel signal of the current frame after delay alignment processing is point B2, and the ending point is E2.

For example, referring to FIG. 5, the first channel of the current frame is the left channel and the second channel is the right channel. The signal from point A2 to point C2 in the right channel signal of the current frame is stretched to the signal of the second alignment process length, and the stretched signal of the second alignment process length is the right channel signal after the stretch process. is used as the signal from point B2 to point C2 in Then the signal from point C2+1 to point E2 in the right channel signal of the current frame is directly used as the signal from point C2+1 to point E2 in the right channel signal after the decompression process. Finally, the signal from point B2 to point E2 in the signal obtained after extension processing is used as the right channel signal of the current frame after delay alignment processing.

If the first channel of the current frame is the right channel and the second channel is the left channel, refer to the above description. Details are not described here.

Second possible case:

FIG. 6 is a schematic diagram of stereo signal processing according to an embodiment of this application. In FIG. 6, for ease of explanation, the point in the second channel signal before the delay alignment process and the point in the second channel signal after the decompression process at the same position have the same coordinates. This does not mean that the signals of points with the same coordinates are the same.

Referring to FIG. 6, the frame length of the current frame is N, the start point of the second channel signal of the current frame is B2=0, and the end point of the second channel signal of the current frame is E2 =N-1. The start point of the second alignment process length is located after the start point B2 of the second channel signal of the current frame, and the start point D2 of the signal of the second alignment process length and the second channel of the current frame The length between the end point E2 of the signal is longer than or equal to the second alignment processing length. The end point of the signal of the second alignment process length is C2=D2+L_pre_target-1. For ease of explanation, the length between the starting point D2 of the signal of the second alignment process length and the starting point B2 of the second channel signal is hereinafter referred to as the second preset length. The second preset length may be greater than 0 and less than or equal to the difference value between the frame length of the current frame and the second alignment processing length, and may be specifically set according to the actual situation. Details are not described here.

The starting point A2 of the signal of the second process length is positioned before the starting point B2 of the second alignment process length, and the starting point A2 of the signal of the second process length and the starting point of the second alignment process length The length between B2 is the absolute value of the inter-channel time difference of the previous frame. The starting point of the signal of the second processing length is A2=D2+abs(prev_itd), and the coordinates of the ending point of the signal of the second processing length are the coordinates of the ending point of the signal of the second alignment processing length. are the same, ie C2=D2+L_pre_target-1.

In the process of delay alignment processing, the second preset length signal starting from H2=B2+abs(prev_itd) in the second channel signal starts from the starting point B2 in the second channel signal after decompression processing. Used directly as a second preset length signal. That is, referring to FIG. 6, the signal from point H2 to point A2-1 in the second channel signal of the current frame is the signal from point B2 to point D2-1 in the second channel signal after decompression processing. used directly as a signal to

Further, the signal from point A2 to point C2 in the second channel signal is stretched to the signal of the second alignment process length, and the stretched signal of the second alignment process length is the second signal after the stretching process. It is used as the second alignment length signal starting from point D2 in the channel signal. That is, the expanded signal of the second alignment processing length is used as the signal from point D2 to point C2 in the second channel signal after expansion processing.

In this embodiment of this application, during signal expansion, the unexpanded signal in the second channel signal of the current frame may remain unchanged, i.e. point C2+ The signal from 1 to point E2 is used directly as the signal from point C2+1 to point E2 in the second channel signal after decompression. E2 is the end point of the second channel signal of the current frame, the frame length of the current frame is N, and E2=N-1.

Finally, in the second channel signal after decompression process, the N sampling points starting from the starting point B2 are used as the second channel signal of the current frame after delay alignment process. That is, the starting point of the first channel signal of the current frame after delay alignment processing is point B2, and the ending point is E2.

For example, referring to FIG. 6, the first channel of the current frame is the left channel and the second channel is the right channel. In the process of delay alignment processing, the signal from point H2 to point A2-1 in the right channel signal of the current frame is directly converted into the signal from point B2 to point D2-1 in the right channel signal after decompression processing. used. The signal from point A2 to point C2 in the right channel signal of the current frame is stretched to the signal of the second alignment process length, and the stretched signal of the second alignment process length is the right channel signal after the newline process. Used as the signal from point D2 to point C2 in the signal. Then the signal from point C2+1 to point E2 in the right channel signal of the current frame is directly used as the signal from point C2+1 to point E2 in the right channel signal after the decompression process. Finally, the signal from point B2 to point E2 in the signal obtained after decompression process is used as the right channel signal of the current frame after delay alignment process.

If the first channel of the current frame is the right channel and the second channel is the left channel, refer to the above description. Details are not described here.

In this embodiment of this application, the method for stretching the signal of the second processing length may be stretching the signal by using a cubic spline interpolation method, quadratic spline interpolation The signal may be stretched by using a method, the signal may be stretched by using a linear interpolation method, or a B-spline interpolation such as a quadratic B-spline interpolation method or a cubic B-spline interpolation method. It should be noted that the signal may also be stretched by using a method. The specific decompression method is not limited in this embodiment of this application, and decompression may be handled using either technique.

In this embodiment of this application, after the delay alignment process is performed, the inter-channel time difference of the current frame may be further quantized and encoded to obtain the code index of the inter-channel time difference of the current frame. Code indices are often written into the codestream. Note that the inter-channel time difference of the current frame may alternatively be quantized and coded in step 101 or quantized and coded here. This is not a limitation in this embodiment of this application.

Specifically, there may be many ways to write the code indices into the codestream. This is not a limitation in this embodiment of this application. For example, after the absolute value of the inter-channel time difference of the current frame is quantized and encoded, the code index of the absolute value of the inter-channel time difference of the current frame is written into the codestream, and the codestream is sent to the decoder side. be. Further, the index of the target channel of the current frame is written into the codestream as the target channel index, or the index of the reference channel of the current frame is written into the codestream as the reference channel index, and the codestream is sent to the decoder side. be done.

The left channel signal of the current frame after delay alignment processing is denoted as _x'L (n) and the right channel signal of the current frame after delay alignment processing is denoted as _x'R (n), where n is Sampling point sequence number, n=0,1,...,N-1. Based on the sign of the inter-channel time difference of the current frame and the sign of the inter-channel time difference of the previous frame, the first channel signal after delay alignment processing may be the left channel signal of the current frame after delay alignment processing. Often denoted as _x'L (n), or the second channel signal after delay alignment processing may be the left channel signal of the current frame after delay alignment processing, denoted as _x'L (n) written down. Similarly, the first channel signal after delay alignment processing may be the right channel signal of the current frame after delay alignment processing, denoted as x′ _R (n), or The second channel signal may be the right channel signal of the current frame after delay alignment processing and is denoted as x' _R (n).

Finally, the first channel signal after delay alignment processing and the second channel signal after delay alignment processing are encoded.

Specifically, the first channel signal after delay alignment processing and the second channel signal after delay alignment processing may be encoded by using an existing stereo encoding method, and the encoding The resulting codestream is sent to the decoder side. The specific encoding method is not limited in this embodiment of this application.

L_next_targetは第1のアライメント処理長であり、cur_itdは現在のフレームのチャンネル間時間差であり、prev_itdは前のフレームのチャンネル間時間差であり、Lは遅延アライメント処理の処理長であり、｜・｜は絶対値をとることを意味する。 Optionally, in this embodiment of this application, when the first alignment process length is not a preset length, the following formula may be satisfied,

L_next_target is the length of the first alignment process, cur_itd is the inter-channel time difference of the current frame, prev_itd is the inter-channel time difference of the previous frame, L is the process length of the delayed alignment process, |·| means to take the absolute value.

L_pre_targetは第2のアライメント処理長であり、cur_itdは現在のフレームのチャンネル間時間差であり、prev_itdは前のフレームのチャンネル間時間差であり、Lは遅延アライメント処理の処理長である。Lは、現在のサンプリングレートにおいて対応するフレーム長N以下であり且つチャンネル間時間差の絶対値の最大値よりも大きいいずれかのプリセット正整数である。例えば、L=290又はL=200である。｜・｜は絶対値をとることを意味する。 When the second alignment process length is not a preset length, the following equation may be satisfied,

L_pre_target is the length of the second alignment process, cur_itd is the inter-channel time difference of the current frame, prev_itd is the inter-channel time difference of the previous frame, and L is the process length of the delayed alignment process. L is any preset positive integer less than or equal to the corresponding frame length N at the current sampling rate and greater than the maximum absolute value of the inter-channel time difference. For example, L=290 or L=200. |·| means taking an absolute value.

Lは遅延アライメント処理の処理長であり、MAX_DELAY_CHANGEは隣接するフレームのチャンネル間時間差の間の最大差分値であり、L_initは遅延アライメント処理のプリセット処理長である。例えば、L_initは、隣接するフレームのチャンネル間時間差の間の最大差分値以上であり、現在のフレームのフレーム長以下でもよく、例えば、290又は200である。｜・｜は絶対値をとることを意味する。 Optionally, in this embodiment of this application, when the process length of the delayed alignment process is not a preset length, the following formula may be satisfied:

L is the processing length of the delay alignment process, MAX_DELAY_CHANGE is the maximum difference value between the inter-channel time differences of adjacent frames, and L_init is the preset process length of the delay alignment process. For example, L_init is greater than or equal to the maximum difference value between the inter-channel time differences of adjacent frames and may be less than or equal to the frame length of the current frame, eg 290 or 200. |·| means taking an absolute value.

MAX_DELAY_CHANGE is a positive integer greater than 0 and may be less than or equal to |T _max -T _min |. T _max corresponds to the maximum inter-channel time difference at the current sampling rate, and T _min corresponds to the minimum inter-channel time difference at the current sampling rate. For example, MAX_DELAY_CHANGE equals 80, 40 or 20. In the example of this application, MAX_DELAY_CHANGE may be 20.

In the following, explanation is provided by using specific embodiments.

Step 1: Perform delay estimation based on the stereo signal of the current frame to determine the inter-channel time difference of the current frame.

See step 101 for the specific content of this step. Details are not described here again.

Step 2: Delay with respect to the first channel signal of the current frame based on the inter-channel time difference of the current frame, if the sign of the inter-channel time difference of the current frame is different from the sign of the inter-channel time difference of the previous frame Perform alignment processing.

Step 3: Delay with respect to the second channel signal of the current frame based on the inter-channel time difference of the previous frame, if the sign of the inter-channel time difference of the current frame is different from the sign of the inter-channel time difference of the previous frame. Perform alignment processing.

Referring to steps 2 and 3, the length between the starting point of the signal of the second alignment process length and the starting point of the second channel signal of the current frame is equal to the second preset length, The length between the starting point of the signal of the first alignment process length and the starting point of the first channel signal of the current frame is equal to the sum of the second preset length and the second alignment process length. Furthermore, the first alignment process length satisfies equation (8), and the second alignment process length satisfies equation (9).

FIG. 7(a) is a schematic diagram of stereo signal processing according to an embodiment of this application. In FIG. 7(a), for ease of explanation, a point in the first channel signal before delay alignment processing and a point in the first channel signal after delay alignment processing at the same position. is noted by using the same coordinates, a point in the second channel signal before delay alignment and a point in the second channel signal after delay alignment at the same position are the same It is marked by using coordinates.

The frame length of the current frame is N, the start point of the first channel signal of the current frame is B1=0, and the end point of the first channel signal of the current frame is E1=N-1. , the starting point of the second channel signal of the current frame is B2=0, and the ending point of the second channel signal of the current frame is E2=N-1. The start point of the signal of the first alignment process length is D1=D2+L_pre_target, the end point of the signal of the first alignment process length is C1=D1+L_next_target-1, and the signal of the first alignment process length is The start point is A1=D1-abs(cur_itd) and the coordinates of the end point of the signal of the first treatment length are the same as the coordinates of the end point of the signal of the first alignment treatment length, i.e. C1= D1+L_next_target-1. The start point of the second alignment run length is D2, and the end point of the second alignment run length is C2=D2+L_pre_target-1. The start point of the second process length signal is A2=D2+abs(prev_itd) and the end point of the second process length signal is C2=D2+L_pre_target-1. For ease of explanation, in the following the length between the starting point D2 of the signal of the second alignment process length and the starting point B2 of the second channel signal is called the second preset length. The second preset length may be greater than 0 and less than or equal to the difference value between the frame length of the current frame and the second alignment processing length, and may be specifically set according to the actual situation. Details are not described here. In this case, as shown in FIG. 7A, the signal of the first processing length is compressed and the signal of the second processing length is expanded.

Referring to FIG. 7(a), in the process of performing delay alignment processing on the first channel signal, the signals from point H1 to point A1-1 in the first channel signal are converted to Directly used as the signal from point B1 to point D1-1 in the first channel signal, H1=B1-abs(cur_itd). The signal from point A1 to point C1 in the first channel signal of the current frame is compressed into a signal of the first alignment process length, and the compressed signal of the first alignment process length is the first channel signal after the compression process. It is used as the signal from point D1 to point C1 in the 1 channel signal. Then the signal from point C1+1 to point E1 in the first channel signal of the current frame is directly used as the signal from point C1+1 to point E1 in the first channel signal after compression processing. be done. Then, the first delay length signal is manually reconstructed based on the first delay length signal before the end point E2 in the second channel signal of the current frame, and the first delay length signal is The reconstructed signal is used as the signal from point E1+1 to point G1 in the first channel signal after compression processing, G1=E1+abs(cur_itd)-1. Finally, the signal from point F1 to point G1 in the signal obtained after delay alignment processing is used as the first channel signal of the current frame after delay alignment processing, F1=B1+abs(cur_itd ).

In the process of performing delay alignment processing on the second channel signal, the second preset length signal starting from H2=B2+abs(prev_itd) in the second channel signal is the second is used directly as a signal of the second preset length starting from the starting point B2 in the channel signal of . That is, referring to FIG. 7(a), the signal from point H2 to point A2-1 in the second channel signal of the current frame corresponds to point B2 to point B2 in the second channel signal after decompression processing. Used directly as signals up to D2-1. The signal from point A2 to point C2 in the second channel signal of the current frame is expanded to the signal of the second alignment process length, and the expanded signal of the second alignment process length is the second channel signal after the expansion process. 2 as the signal from point D2 to point C2 in channel signal 2. Then the signal from point C2+1 to point E2 in the second channel of the current frame is directly used as the signal from point C2+1 to point E2 in the second channel signal after decompression processing. be. Finally, the signal from point B2 to point E2 in the signal obtained after delay alignment processing is used as the second channel signal of the current frame after delay alignment processing.

Referring to FIG. 7(a), in this embodiment of this application, the starting point of the second alignment process length may also be the starting point of the second channel signal, i.e. D2=B2 and D1=B1+ It can be L_pre_target. In this case, as shown in FIG. 7B, the signal of the first processing length is compressed and the signal of the second processing length is expanded.

FIG. 7(b) is a schematic diagram of stereo signal processing according to an embodiment of this application. In FIG. 7(b), for ease of explanation, a point in the first channel signal before delay alignment processing and a point in the first channel signal after delay alignment processing at the same position. is noted by using the same coordinates, a point in the second channel signal before delay alignment and a point in the second channel signal after delay alignment at the same position are the same It is marked by using coordinates.

In FIG. 7(b), the frame length of the current frame is N, the starting point of the first channel signal of the current frame is B1=0, and the ending point of the first channel signal of the current frame is E1=N-1. The start point of the signal for the first alignment length is D1=B1+L_pre_target, the end point of the signal for the first alignment length is C1=B1+L_pre_target+L_next_target-1, and the the starting point of the signal is A1=B1+L_pre_target-abs(cur_itd), the coordinates of the ending point of the signal of the first process length are the same as the coordinates of the ending point of the signal of the first alignment process length, That is, C1=B1+L_pre_target+L_next_target-1.

The starting point of the second channel signal of the current frame is B2=0, and the ending point of the second channel signal of the current frame is E2=N-1. The start point of the second alignment length is the start point B2 of the second channel signal, and the end point of the second alignment length is C2=B2+L_pre_target-1. The start point of the second process length signal is A2=B2+abs(prev_itd) and the end point of the second process length signal is C2=B2+L_pre_target-1.

Referring to FIG. 7(b), in the process of performing delay alignment processing on the first channel signal, the signals from point H1 to point A1-1 in the first channel signal are converted to Directly used as the signal from point B1 to point D1-1 in the first channel signal, H1=B1-abs(cur_itd). The signal from point A1 to point C1 in the first channel signal of the current frame is compressed into a signal of the first alignment process length, and the compressed signal of the first alignment process length is the first channel signal after the compression process. It is used as the signal from point D1 to point C1 in the 1 channel signal. Then the signal from point C1+1 to point E1 in the first channel signal of the current frame is directly used as the signal from point C1+1 to point E1 in the first channel signal after compression processing. be done. Then, the first delay length signal is manually reconstructed based on the first delay length signal before the end point E2 in the second channel signal of the current frame, and the first delay length signal is The reconstructed signal is used as the signal from point E1+1 to point G1 in the first channel signal after compression processing, G1=E1+abs(cur_itd)-1. Finally, the signal from point F1 to point G1 in the signal obtained after delay alignment processing is used as the first channel signal of the current frame after delay alignment processing, F1=B1+abs(cur_itd ).

In the process of performing a delay alignment process on the second channel signal, the signal from point A2 to point C2 in the second channel signal of the current frame is decompressed into a signal of the second alignment process length; The decompressed signal of the second alignment processing length is used as the signal from point B2 to point C2 in the second channel signal after decompression processing. Then the signal from point C2+1 to point E2 in the second channel of the current frame is directly used as the signal from point C2+1 to point E2 in the second channel signal after decompression processing. be. Finally, the signal from point B2 to point E2 in the signal obtained after delay alignment processing is used as the second channel signal of the current frame after delay alignment processing.

To add smoothing between frames, a transition interval may also be set, the transition interval length being ts. Optionally, the length of the smoothed transition interval may be further set, the length of the smoothed transition interval being Ts2. For the specific method, refer to the above description. Details are not described here.

In this embodiment of this application, if it is determined that the sign of the current frame's inter-channel time difference is the same as the sign of the previous frame's inter-channel time difference, then the delay alignment process is applied to the current frame's inter-channel time difference. and the signal of the target channel of the current frame based on the inter-channel time difference of the previous frame. In this case, the target channel of the current frame and the target channel of the previous frame are the same channel. The specific delay alignment processing method is not limited in this embodiment of this application.

For example, possible processing methods are as follows.

Step 1: Use the estimated inter-channel time difference of the current frame as the inter-channel time difference of the current frame.

Step 2: Select the target channel and reference channel of the current frame based on the inter-channel time difference of the current frame and the inter-channel time difference of the previous frame. The inter-channel time difference of the current frame is noted as cur_itd and the inter-channel time difference of the previous frame is noted as prev_itd. Specifically, if cur_itd=0, the target channel of the current frame matches the target channel of the previous frame. For example, the target channel index of the current frame is noted as target_idx, the target channel index of the previous frame is noted as prev_target_idx, target_idx=prev_target_idx. If cur_itd<0, the target channel for the current frame is the left channel. For example, the target channel index of the current frame is noted as target_idx and target_idx=0. If cur_itd>0, the target channel for the current frame is the right channel. For example, the target channel index of the current frame is noted as target_idx and target_idx=1.

Moreover, the target channel index of the current frame may be further encoded and written into the codestream, and the codestream is sent to the decoder side.

Step 3: Perform delay alignment processing on the signal of the selected target channel based on the inter-channel time difference of the current frame and the inter-channel time difference of the previous frame. Specifically, this step may be as follows.

The preprocessed time-domain signal of the channel corresponding to the target channel is used as the signal of the target channel, and the preprocessed time-domain signal of the channel corresponding to the reference channel is used as the signal of the reference channel. For example, if the target channel is the left channel, the preprocessed time-domain signal of the left channel is used as the signal of the target channel, and if the reference channel is the right channel, the preprocessed time-domain signal of the right channel is is used as the reference channel signal. If the target channel is the right channel, the preprocessed time-domain signal of the right channel is used as the signal of the target channel, and if the reference channel is the left channel, the preprocessed time-domain signal of the left channel is Used as reference channel signal.

If abs(cur_itd) is equal to abs(prev_itd), the target channel's signal is not compressed or expanded. The signal at point abs(cur_itd) is manually reconstructed based on the reference channel signal and used as the signal from point B+N to point B+N+abs(cur_itd)-1 of the target channel signal in the current frame be done. The target channel signal of the current frame is directly delayed by abs(cur_itd) sampling points and used as the target channel signal of the current frame after delay alignment processing. B represents the coordinates of the starting point in the target channel signal of the current frame, N represents the frame length of the current frame, and abs() represents an absolute value operation. The current frame reference channel signal is used directly as the current frame reference channel signal after delay alignment processing.

If abs(cur_itd) is less than abs(prev_itd), the signal from point B+abs(prev_itd)-abs(cur_itd) to point B+L-1 of the buffered target channel signal is L points , which is used as the signals of the first L points of the target channel after the decompression process. The signal from point B+L to point B+N-1 in the target channel signal is directly used as the signal from point B+L to point B+N-1 in the target channel signal after expansion processing . The signal at point abs(cur_itd) is manually reconstructed based on the reference channel signal and used as the signal from point B+N to point B+N+abs(cur_itd)-1 of the target channel after stretching be done. The N-point signal starting from point B+abs(cur_itd) in the target channel signal after decompression process is used as the target channel signal of the current frame after delay alignment process. The current frame reference channel signal is used directly as the current frame reference channel signal after delay alignment processing. B represents the coordinates of the starting point in the target channel signal of the current frame, N represents the frame length of the current frame, and L represents the process length of the delay alignment process.

If abs(cur_itd) is greater than abs(prev_itd), the signal from point B+abs(prev_itd)-abs(cur_itd) of the buffered target channel signal to point B+L-1 is L points is compressed into a signal of length , which is used as the signal of the first L points of the target channel after the compression process. The signal from point B+L to point B+N-1 in the target channel signal is directly used as the signal from point B+L to point B+N-1 in the target channel signal after compression processing . The signal at point abs(cur_itd) is manually reconstructed based on the reference channel signal and used as the signal from point B+N to point B+N+abs(cur_itd)-1 of the target channel after compression processing be done. The N-point signal starting from point B+abs(cur_itd) in the target channel after compression process is used as the target channel signal of the current frame after delay alignment process. The current frame reference channel signal is used directly as the current frame reference channel signal after delay alignment processing. B represents the coordinates of the starting point in the target channel signal of the current frame, N represents the frame length of the current frame, and L represents the process length of the delay alignment process.

To add smoothing between frames, a transition interval may be set here, the transition interval length being ts. The first transition interval length may be set to a preset positive integer, and the preset positive integer may be set based on experience by those skilled in the art. For example, the first transition interval length may alternatively be calculated based on the inter-channel time difference of the current frame. For example, ts=abs(cur_itd)/2. Similarly, a smoothed transition interval may also be set to add smoothing between the actual signal and the reconstructed signal, the length of the smoothed transition interval being Ts2. The length of the smoothed transition interval may be set to a preset positive integer. For example, Ts2 is set to 10. Step 3 of then performing delay alignment processing on the signal of the selected target channel based on the inter-channel time difference of the current frame and the inter-channel time difference of the previous frame may be modified as follows. .

If abs(cur_itd) is less than abs(prev_itd), the signal from point B-ts+abs(prev_itd)-abs(cur_itd) to point B+L-ts-1 of the buffered target channel signal is It is expanded to a signal of length L, which is used as the signal from point B-ts to point B+L-ts-1 of the target channel after the expansion process. The signal from the point B+L-ts to the point B+N-Ts2-1 in the target channel signal is the point B+L-ts to the point B+N-Ts2-1 in the target channel signal after decompression. used directly as a signal to The signal at point Ts2 is generated based on the reference channel signal and the target channel signal, and is used as the signal from point B+N-Ts2 to point B+N-1 of the target channel after decompression processing. The signal at point abs(cur_itd) is manually reconstructed based on the reference channel signal and used as the signal from point B+N to point B+N+abs(cur_itd)-1 of the target channel after stretching be done. The N-point signal starting from point B+abs(cur_itd) in the target channel after decompression process is used as the target channel signal of the current frame after delay alignment process. The current frame reference channel signal is used directly as the current frame reference channel signal after delay alignment processing. B represents the coordinates of the starting point in the target channel signal of the current frame, N represents the frame length of the current frame, and L represents the process length of the delay alignment process.

If abs(cur_itd) is greater than abs(prev_itd), the signal from point B-ts+abs(prev_itd)-abs(cur_itd) to point B+L-ts-1 of the buffered target channel signal is Compressed to a signal of length L points, which is used as the signal from point B-ts to point B+L-ts-1 of the target channel after the compression process. The signal from point B+L-ts to point B+N-Ts2-1 in the target channel signal is from point B+L-ts to point B+N-Ts2-1 in the target channel after compression processing used directly as a signal for The signal at point Ts2 is generated based on the reference channel signal and the target channel signal, and is used as the signal from point B+N-Ts2 to point B+N-1 of the target channel after compression processing. The signal at point abs(cur_itd) is manually reconstructed based on the reference channel signal and used as the signal from point B+N to point B+N+abs(cur_itd)-1 of the target channel after compression processing be done. The N-point signal starting from point B+abs(cur_itd) in the target channel after compression process is used as the target channel signal of the current frame after delay alignment process. The current frame reference channel signal is used directly as the current frame reference channel signal after delay alignment processing. B represents the coordinates of the starting point in the target channel signal of the current frame, N represents the frame length of the current frame, and L represents the process length of the delay alignment process.

The signal at point Ts2 is generated based on the reference channel signal and the target channel signal, and is used as the signal from point B+N-Ts2 to point B+N-1 of the target channel after compression or decompression processing. , specifically as follows. The signal at point Ts2 is the signal from point B+N-Ts2 to point B+N-1 on the target channel and the signal from point B+N-abs(cur_itd)-Ts2 to point B+N-abs(cur_itd) on the reference channel. )-1 and used as the signals from point B+N-Ts2 to point B+N-1 of the target channel after compression or decompression. The signal at point abs(cur_itd) is manually reconstructed based on the reference channel signal, and the signal from point B+N to point B+N+abs(cur_itd)-1 of the target channel after compression or decompression processing may be specifically as follows. The signal at point abs(cur_itd) is generated based on the signals from point B+N-abs(cur_itd) of the reference channel to point B+N-1, and point B+ of the target channel after compression or decompression processing. Used as signal from N to point B+N+abs(cur_itd)-1.

The left channel signal of the current frame after delay alignment processing is denoted as _x'L (n) and the right channel signal of the current frame after delay alignment processing is denoted as _x'R (n), where n is Sampling point sequence number, n=0,1,...,N-1. According to the sign of the inter-channel time difference of the current frame, the target channel signal after delay alignment processing may be the left channel signal of the current frame after delay alignment processing, denoted as x′ _L (n), or The target channel signal after delay alignment processing may be the right channel signal of the current frame after delay alignment processing, denoted as x' _R (n). Similarly, the reference channel signal after delay alignment processing may be the left channel signal of the current frame after delay alignment processing, denoted as x′ _L (n), or the reference channel signal after delay alignment processing The signal may be the right channel signal of the current frame after delay alignment processing, denoted as x' _R (n).

The final obtained signals after delay alignment processing are used for time domain downmix processing to obtain primary channel signals and secondary channel signals after time domain downmix processing. The primary channel signal and the secondary channel signal are encoded separately to encode the input stereo signal.

Embodiments of this application may also be applicable to the decoding process, which may be considered the inverse process of the encoding process, and is described in detail below.

FIG. 8 shows a stereo signal processing method according to an embodiment of this application, including:

Step 801: Determine the inter-channel time difference of the current frame based on the received codestream, the inter-channel time difference of the current frame being the difference between the first channel signal of the current frame and the second channel signal of the current frame. is the time difference between

In step 801, the first channel signal of the current frame and the second channel signal of the current frame may be further obtained through decoding based on the received codestream.

This embodiment of this application states that the method corresponds to an encoding method for encoding a first channel signal after delay alignment processing and a second channel signal after delay alignment processing by the encoder side. The terms do not set limitations on the method for decoding the first channel signal of the current frame and the second channel signal of the current frame. The decoded first channel signal of the current frame, i.e., the first channel signal before delay recovery processing, corresponds to the encoded first channel signal after encoder-side delay alignment processing. . The decoded second channel signal of the current frame, i.e. the second channel signal before delay recovery processing, corresponds to the encoded second channel signal after delay alignment processing on the encoder side. .

In step 801, the method for decoding the inter-channel time difference of the current frame should correspond to the encoding method on the encoder side. For example, if the encoder side writes the code index of the absolute value of the inter-channel time difference of the current frame and the reference channel index into the codestream, and sends the codestream to the decoder side, the decoder side will write the codestream based on the received codestream. to decode the absolute value of the inter-channel time difference of the current frame and the reference channel index.

Alternatively, if the encoder side writes the code index of the absolute value of the inter-channel time difference of the current frame and the target channel index into the codestream and sends the codestream to the decoder side, the decoder side writes Based on this, decode the absolute value of the inter-channel time difference of the current frame and the target channel index.

Alternatively, if the encoder side writes the code index of the inter-channel time difference of the current frame into the codestream and sends the codestream to the decoder side, the decoder side can calculate the inter-channel time difference of the current frame based on the received codestream. Decode the time difference.

Refer to the description herein for the scheme for determining the inter-channel time difference of the previous frame. No further details are given.

Step 802: A first channel signal of the current frame based on the inter-channel time difference of the current frame, if the sign of the inter-channel time difference of the current frame is different from the sign of the inter-channel time difference of the frame before the current frame. and perform delay recovery processing on the second channel signal of the current frame based on the inter-channel time difference of the previous frame, and perform delay recovery processing on the first channel signal of the current frame. A target channel signal, the second channel signal is on the same channel as the target channel signal of the previous frame.

In step 802, the sign may indicate a plus sign (+) or a minus sign (-). In this embodiment of this application, the previous frame is located before and adjacent to the current frame. For ease of explanation, hereinafter the channel corresponding to the first channel signal of the current frame will be referred to as the first channel, and the channel corresponding to the second channel signal of the current frame will be referred to as the second channel. called a channel. The first channel is the target channel of the current frame, and may also be called the target channel of the next frame, or the designated target channel of the current frame, or the target channel of the current frame. It should be noted that other channels than the target channel of the frame before the frame may be called. Correspondingly, the second channel is the reference channel of the current frame, the second channel is the channel within the two channels of the stereo signal and the same as the target channel of the previous frame, and , may be called the target channel of the previous frame, or may be called the designated reference channel of the current frame, or may be called a channel other than the target channel of the current frame. For example, if the target channel in the previous frame is the left channel, the first channel signal is the right channel signal in the current frame and the second channel signal is the left channel signal in the current frame. If the target channel in the previous frame is the right channel, the first channel signal is the left channel signal in the current frame and the second channel signal is the right channel signal in the current frame.

In step 802, when the decoder side decodes the inter-channel time difference of the current frame based on the received codestream, the decoder side determines that the sign of the inter-channel time difference of the current frame is equal to the inter-channel time difference of the previous frame. It may be determined directly whether it is the same as the sign.

A decoder side decodes the absolute value of the inter-channel time difference of the current frame and the reference channel of the current frame or the absolute value of the inter-channel time difference of the current frame and the target channel index of the current frame according to the received codestream. , the decoder side selects the channel of the current frame based on the reference channel of the current frame and the reference channel index of the previous frame, or based on the target channel of the current frame and the reference channel index of the previous frame. It is necessary to determine whether the sign of the inter-channel time difference is the same as the sign of the inter-channel time difference of the previous frame.

It is used here as an example that the absolute value of the inter-channel time difference of the current frame and the reference channel index are decoded. Specifically, it is determined that the sign of the inter-channel time difference of the current frame is different from the sign of the inter-channel time difference of the previous frame if the reference channel index of the current frame is not equal to the reference channel index of the previous frame. . If the reference channel index of the current frame is equal to the reference channel index of the previous frame, it is determined that the sign of the inter-channel time difference of the current frame is the same as the sign of the inter-channel time difference of the previous frame. For other cases, see the discussion here. No further details are given.

The decoder-side delay recovery process corresponds to the encoder-side delay alignment process. If the encoder side performs compression, the decoder side needs to decompress the compressed signal. Similarly, if the encoder side performs decompression, the decoder side needs to compress the decompressed signal.

In this embodiment of this application, there are multiple methods for performing delay recovery processing on the first channel signal and the second channel signal in the decoding process, which are described separately below. be done.

1. Perform delay recovery processing on the first channel signal of the current frame based on the inter-channel time difference of the current frame.

Specifically, the signal of the third processing length within the first channel signal of the current frame is subjected to a third alignment to obtain the first channel signal of the current frame after delay recovery processing. Decompressed to process length signal. A third process length is determined based on the inter-channel time difference of the current frame and a third alignment process length, where the third process length is less than the third alignment process length.

In the decoding process, the third process length may be the difference between the third alignment process length and the absolute value of the inter-channel time difference of the current frame, the third alignment process length may be the preset length, Alternatively, it may be determined by another method, for example, it may be determined according to equation (8). In this embodiment of this application, the third alignment length is less than or equal to the frame length of the current frame. When the third alignment process length is set in advance, the third alignment process length may be L, L/2, L/3, or any length of L or less. L is any preset positive integer less than or equal to the corresponding frame length N at the current sampling rate and greater than the maximum absolute value of the inter-channel time difference. For example, L=290 or L=200. In this embodiment of this application, L may be set to different values for different sampling rates, or may be a uniform value. In general, the values may be preset based on the experience of those skilled in the art. For example, L is set to 290 when the sampling rate is 16KHz. In this case, the third alignment processing length is L/2=145.

In this embodiment of this application, the starting point of the signal of the third treatment length is located after the starting point of the signal of the third alignment treatment length, and the starting point of the signal of the third treatment length and the third The length between the start point of the alignment process length signal is the absolute value of the inter-channel time difference of the current frame.

In this embodiment of this application, the third alignment process length may be represented by L2_next_target and the fourth alignment process length may be represented by L2_pre_target. It should be noted that the first alignment process length on the encoder side is actually equal to the third alignment process length on the decoder side corresponding to the encoder side. Correspondingly, the second alignment process length on the encoder side is actually equal to the fourth alignment process length on the decoder side corresponding to the encoder side. For ease of explanation, different notations are used here to represent length. The inter-channel time difference of the current frame is cur_itd, and abs(cur_itd) represents the absolute value of the inter-channel time difference of the current frame. For ease of explanation, abs(cur_itd) will be referred to as the first delay length in the following discussion. The inter-channel time difference of the previous frame is prev_itd, and abs(prev_itd) represents the absolute value of the inter-channel time difference of the previous frame. For ease of explanation, abs(prev_itd) is referred to as the second delay length in the following discussion.

In the decoding process, the specific position of the third processing length signal may be determined based on different actual conditions, which are described separately below.

First possible case:

FIG. 9 is a schematic diagram of stereo signal processing according to an embodiment of this application. In FIG. 9, for ease of explanation, a point in the first channel signal before delay recovery processing and a point in the first channel signal after decompression processing at the same position have the same coordinates. This does not mean that the signals of points with the same coordinates are the same.

In FIG. 9, the frame length of the current frame is N, the starting point of the first channel signal of the current frame is B3=0, and the ending point of the first channel signal of the current frame is E3=N. -1. The starting point of the signal of the third processing length is located at the starting point B3 of the first channel signal of the current frame, and the ending point of the signal of the third processing length is C3=B3-abs(cur_itd)+L2_next_target -1.

In FIG. 9, the starting point of the third alignment length is A3=B3-abs(cur_itd), and the end point of the signal of the third alignment length is C3, which is the It is the same as the coordinates of the end point of the signal.

In the process of delay recovery processing, referring to FIG. 9, the signal from point B3 to point C3 in the first channel signal of the current frame is decompressed into a signal of third alignment processing length, and the third alignment The process length stretch signal is used as a signal of the third alignment process length starting from the starting point A3 of the third alignment process length in the first channel signal after the stretch process, i.e. It is used as the signal from the starting point A3 to the point C3 of the third alignment process length in the first channel signal.

In this embodiment of this application, during signal decompression, the signal from point C3+1 to point E3 in the first channel signal of the current frame is the signal from point C3 in the first channel signal after decompression processing. It may be used directly as a signal from +1 to point E3.

Finally, in the first channel signal after decompression, the N sampling points starting from the starting point A3 are used as the first channel signal of the current frame after delay recovery. That is, the starting point of the first channel signal of the current frame after delay recovery processing is point G3, where G3=E3-abs(cur_itd).

In general, the starting point of the signal of the third processing length may be located after the starting point of the first channel signal. However, when the starting point of the signal of the third processing length is located after the starting point of the first channel signal, the starting point of the signal of the third processing length and the ending point of the first channel signal of the current frame is greater than or equal to the difference between the third alignment process length and the absolute value of the inter-channel time difference of the current frame, which will be explained in detail below. .

Second possible case:

FIG. 10 is a schematic diagram of stereo signal processing according to an embodiment of this application. In FIG. 10, for ease of explanation, a point in the first channel signal before delay recovery processing and a point in the first channel signal after decompression processing at the same position have the same coordinates. This does not mean that the signals of points with the same coordinates are the same.

In FIG. 10, the frame length of the current frame is N, the starting point of the first channel signal of the current frame is B3=0, and the ending point of the first channel signal of the current frame is E3=N. -1.

In FIG. 10, the starting point of the third processing length is D3 and the ending point of the signal of the third processing length is C3=D3-abs(cur_itd)+L2_next_target-1. A3 is the starting point of the signal of the third alignment process length, A3=D3-abs(cur_itd). The coordinates of the end point of the signal of the third alignment process length are the same as the coordinates of the end point C3 of the signal of the third process length, i.e. C3=A3+L2_next_target-1=D3-abs(cur_itd)+ It is L2_next_target-1. The starting point D3 of the signal of the third processing length is located after the starting point B3 of the signal of the first channel of the current frame, and the starting point of the signal of the third processing length and the first channel of the current frame The length between the end points of the signal is greater than or equal to the difference between the third alignment process length and the absolute value of the inter-channel time difference of the current frame. The length between the starting point D3 of the signal of the third processing length and the starting point B3 of the first channel signal of the current frame is the third preset length. The third preset length may be determined based on the actual situation, the third preset length is greater than 0 and less than or equal to the difference between the frame length of the current frame and the third processing length be. In FIG. 10, the fact that the third preset length is greater than the absolute value of the inter-channel time difference of the current frame is used as an illustrative example. For other cases of the third preset length, see the description here.

In FIG. 10, the length between the starting point D3 of the signal of the third processing length and the starting point B3 of the first channel signal of the current frame is the third preset length, and the third alignment processing The starting point of the long signal is A3, where A3=A3=D3-abs(cur_itd). H3 is located before the starting point B3 of the first channel signal of the current frame, the length between H3 and A3 is the third preset length, the length between H3 and B3 is the absolute value of the inter-channel time difference of the current frame, ie H3=B3-abs(cur_itd).

The point A3 may be located before the starting point B3 of the first channel signal of the current frame, and the length between the point A3 and the starting point B3 of the first channel signal of the current frame is Note that it is less than or equal to the absolute value of the inter-channel time difference of the current frame. Point A3 may be located at the starting point B3 of the first channel signal of the current frame. The point A3 may alternatively be located after the starting point B3 of the first channel signal of the current frame and the length between the point A3 and the starting point B3 of the first channel signal of the current frame is less than or equal to the difference between the frame length of the current frame and the third alignment process length. For the case where the point A3 is at the above position, refer to the description here. No further details are given.

In the process of delay recovery processing, the signal of the third preset length starting from the starting point B3 of the first channel signal of the current frame is the third preset length before the starting point A3 of the third alignment processing length. May be used as a signal. Referring to FIG. 10, the signal from point B3 to point D3-1 in the first channel signal of the current frame corresponds to point H3 to point A3-1 in the first channel signal after delay recovery processing. used as a signal for

Then, the signal of the third process length starting from the starting point within the first channel signal of the current frame may be stretched to the signal of the third alignment process length, the stretched signal of the third alignment process length is used as the signal of the third alignment process length starting from the starting point of the third alignment process length in the first channel signal after decompression. Referring to FIG. 10, the signal from the starting point D3 to the point C3 in the first channel signal of the current frame is expanded to the signal of the third alignment processing length, and the first channel signal after the expansion processing is is used as the signal from point A3 to point C3 in

Then the signal from point C3+1 to point E3 in the first channel signal of the current frame is used as the signal from point C3+1 to point E3 in the first channel signal after decompression. be.

Finally, the N-point signal starting from the starting point H3 in the first channel signal after decompression process is used as the first channel signal of the current frame after delay recovery process. The starting point of the first channel signal of the current frame after delay recovery processing is point G3, where G3=E3-abs(cur_itd).

2. Perform delay recovery processing on the second channel signal of the current frame based on the inter-channel time difference of the previous frame.

Specifically, the signal of the fourth processing length in the second channel signal of the current frame is subjected to the fourth alignment to obtain the second channel signal of the current frame after delay recovery processing. Compressed to process length signal. A fourth process length is determined based on the inter-channel time difference of the previous frame and a fourth alignment process length, where the fourth process length is greater than the fourth alignment process length.

In this embodiment of this application, the fourth process length may be the sum of the absolute value of the inter-channel time difference of the previous frame and the fourth alignment process length. Further, the starting point of the signal of the fourth process length is positioned before the starting point of the signal of the fourth alignment process length, and the starting point of the signal of the fourth process length and the signal of the fourth alignment process length is the absolute value of the inter-channel time difference of the previous frame.

It should be noted that the fourth alignment process length may be a preset length, or may be determined in some other manner, for example, according to equation (9). In this embodiment of this application, when the fourth alignment process length is less than or equal to the frame length of the current frame and the fourth alignment process length is preset, the fourth alignment process length is L, L/ Any length less than 2, L/3 or L is acceptable.

In this embodiment of this application, the starting point of the signal of the fourth alignment process length may be located at the starting point of the second channel signal of the current frame, or the second channel signal of the current frame. It may be located after the start of the signal. However, in any case, the length between the start point of the signal of the fourth alignment process length and the end point of the second channel signal of the current frame is greater than or equal to the fourth alignment process length, and these are described separately below.

First possible case:

FIG. 11 is a schematic diagram of stereo signal processing according to an embodiment of this application. In FIG. 11, for ease of explanation, a point in the second channel signal before delay recovery processing and a point in the second channel signal after compression processing at the same position have the same coordinates. This does not mean that the signals of points with the same coordinates are the same.

In FIG. 11, the frame length of the current frame is N, the start point of the second channel signal of the current frame is B4=0, and the end point of the second channel signal of the current frame is E4=N. -1.

The start point of the fourth alignment length is located at the start point B4 of the second channel signal of the current frame, and the end point of the signal of the fourth alignment length is C4=B4+L2_pre_target-1. The starting point of the signal of the fourth treatment length is A4=B4-abs(prev_itd), the ending point of the signal of the fourth treatment length is C4, which is the start of the signal of the fourth alignment treatment length Same as point coordinates.

In the process of the delay recovery process, the signal of the fourth process length starting from the starting point of the signal of the fourth process length may be compressed into the signal of the fourth alignment process length, The compressed signal is used as a fourth alignment length signal starting from point B4 in the second channel signal after compression. Referring to FIG. 11, the signal from point A4 to point C4 is compressed into a signal of the fourth alignment length, and the compressed signal of the fourth alignment length is within the second channel signal after compression processing. is used as the signal from point B4 to point C4 of .

Then the signal from point C4+1 to point E4 in the second channel signal of the current frame is used as the signal from point C4+1 to point E4 in the second channel signal after compression processing. be.

Finally, the N-point signal starting from the starting point B4 in the second channel signal after compression processing is used as the second channel signal of the current frame after delay recovery processing, i.e. delay alignment processing The starting point of the second channel signal of the current frame after is point B4 and the ending point is E4.

Second possible case:

FIG. 12 is a schematic diagram of stereo signal processing according to an embodiment of this application. In FIG. 12, for ease of explanation, the point in the second channel signal of the current frame before the delay recovery process and the second channel signal of the current frame after the compression process are at the same position. Points within are marked by using the same coordinates, but this does not mean that the signals of points with the same coordinates are the same.

In FIG. 12, the frame length of the current frame is N, the starting point of the first channel signal of the current frame is B4=0, and the ending point of the first channel signal of the current frame is E4=N. -1.

The start point of the fourth alignment length is D4, and the end point of the signal of the fourth alignment length is C4=D4+L2_pre_target-1. The starting point D4 of the signal of the fourth alignment process length is located after the starting point B4 of the second channel signal of the current frame, and the starting point D4 of the signal of the fourth alignment process length and the second channel signal of the current frame The length between the second channel signal and the end point E4 is longer than or equal to the fourth alignment processing length.

For ease of explanation, the length between the starting point D4 of the signal of the fourth alignment process length and the starting point B4 of the second channel signal of the current frame is the fourth preset length, The fourth preset length is greater than 0 and less than or equal to the difference between the frame length of the current frame and the fourth alignment process length.

The starting point of the signal of the fourth treatment length is A4=D4-abs(prev_itd), the ending point of the signal of the fourth treatment length is C4, which is the starting point of the fourth alignment treatment length signal are the same as the coordinates of

In FIG. 12, the length between point H4 and point A4 is the fourth preset length, and the length between point H4 and point B4 is the absolute value of the inter-channel time difference of the previous frame. , that is, H4=B4-abs(prev_itd).

In the process of delay recovery processing, the fourth preset length signal before the starting point of the fourth processing length signal in the second channel signal of the current frame is the second channel signal after compression processing may be used as a signal of a fourth preset length starting from point B4 in. Referring to FIG. 12, the signals from point H4 to point A4-1 are used as the signals from point B4 to point D4-1 in the second channel signal after compression processing.

Then, the fourth process length signal starting from the starting point of the fourth process length signal in the second channel signal of the current frame may be compressed into a fourth alignment process length signal, The 4 alignment length compressed signal is used as the fourth alignment length signal starting from the starting point of the fourth alignment length signal in the second channel signal after compression processing. Referring to FIG. 12, the signal from point A4 to point C4 in the second channel signal of the current frame is compressed into a signal of the fourth alignment length, and the compressed signal of the fourth alignment length is It is used as the signal from point D4 to point C4 in the second channel signal after compression processing.

Then the uncompressed signal in the second channel signal of the current frame remains unchanged, i.e. the signal from point C4+1 to point E4 in the second channel signal of the current frame is subjected to the compression process. is used as the signal from point C4+1 to point E4 in the second channel signal after .

Finally, the N-point signal starting from the starting point B4 in the second channel signal after compression processing is used as the second channel signal of the current frame after delay recovery processing.

In the following, explanation is provided by using specific embodiments.

Step 1: Determine the inter-channel time difference of the current frame based on the received codestream.

See step 801 for the specific content of this step. Details are not described here again.

Step 2: Delay with respect to the first channel signal of the current frame based on the inter-channel time difference of the current frame, if the sign of the inter-channel time difference of the current frame is different from the sign of the inter-channel time difference of the previous frame Carry out the recovery process.

Step 3: Delay with respect to the second channel signal of the current frame based on the inter-channel time difference of the previous frame, if the sign of the inter-channel time difference of the current frame is different from the sign of the inter-channel time difference of the previous frame. Carry out the recovery process.

In steps 2 and 3, the length between the starting point of the signal of the fourth alignment process length and the starting point of the second channel signal of the current frame is equal to the fourth preset length, and the third The length between the start of the alignment process length signal and the start of the first channel signal of the current frame is equal to the sum of the fourth preset length and the fourth alignment process length. Furthermore, the third alignment process length satisfies equation (8), and the fourth alignment process length satisfies equation (9). In this case, as shown in FIG. 13, the signal of the third processing length is expanded and the signal of the fourth processing length is compressed. In FIG. 13, the example where the starting point of the fourth alignment process length is located at the starting point of the first channel signal of the current frame is used for illustration. Delay recovery processing when the starting point of the fourth alignment length is located after the starting point B4 of the second channel signal of the current frame when the starting point of the fourth alignment length is located at another position is performed on the second channel signal and in this case the delay recovery process is performed on the first channel signal. Details are not described here.

In FIG. 13, the frame length of the current frame is N, the start point of the second channel signal of the current frame is B4=0, and the end point of the second channel signal of the current frame is E4=N. -1. The starting point of the signal of the fourth alignment process length is located at the starting point B4 of the signal of the second channel of the current frame, and the ending point of the signal of the fourth alignment process length is C4=B4+L2_pre_target-1. be. The starting point of the signal of the fourth processing length is A4=B4-abs(prev_itd) and the ending point of the signal of the fourth processing length is C4=B4+L2_pre_target-1.

The starting point of the first channel signal of the current frame is B3=0, and the ending point of the first channel signal of the current frame is E3=N-1. The starting point of the third processing length signal is D3=B4+L2_pre_target and D3=C4+1. The end point of the signal of the third treatment length is C3=A3+L2_next_target-1, the start point of the signal of the third treatment length is A3=D3-abs(cur_itd), the signal of the third treatment length end point is C3=A3+L_next_target-1.

In the process of delay recovery processing, for the first channel signal, the signal from point B3 to point D3-1 in the first channel signal of the current frame is the point in the first channel signal after decompression processing Directly used as signal from H3 to point A3-1, H3=A3-L2_pre_target.

Then, the signal from point D3 to point C3 in the first channel signal of the current frame is stretched to the signal of the third alignment process length, and the stretched signal of the third alignment process length is is used as the signal from point A3 to point C3 in the first channel signal of .

Then the signal from point C3+1 to point E3 in the first channel signal of the current frame is used as the signal from point C3+1 to point E3 in the first channel signal after decompression. be.

Finally, the N-point signal starting from the starting point A3 in the first channel signal after the extension process is used as the first channel signal of the current frame after the delay recovery process. The starting point of the first channel signal of the current frame after delay recovery processing is point A3, the ending point is point G3, and G3=E3-abs(cur_itd).

In the process of delay recovery processing, for the second channel signal, the signal from point A4 to point C4 is compressed into a signal of the fourth alignment length, and the compressed signal of the fourth alignment length is compressed after the compression processing. is used as the signal from point B4 to point C4 in the second channel signal of .

Then the signal from point C4+1 to point E4 in the second channel signal of the current frame is used as the signal from point C4+1 to point E4 in the second channel signal after compression processing. be.

Finally, the N-point signal starting from the starting point B4 in the second channel signal after compression processing is used as the second channel signal of the current frame after delay recovery processing, i.e. delay recovery processing The starting point of the second channel signal of the current frame after is point B4 and the ending point is point E4.

It should be noted that in this embodiment of this application the method of signal expansion or compression is not limited. For details, refer to the explanations in steps 101 and 102 . Details are not described here again.

In this embodiment of this application, reference is made to the above description when there is a transition interval length between frames. Details are not described here.

Based on the same technical concept, the embodiments of this application further provide a stereo signal processing device, and the stereo signal processing device may perform the steps of the method in FIG.

As shown in FIG. 14, the embodiment of this application provides a schematic structural diagram of a stereo signal processing device.

Referring to FIG. 14, the stereo signal processing device 1400 includes:
a delay estimation unit 1401 configured to perform delay estimation based on the stereo signal of the current frame to determine the inter-channel time difference of the current frame;
for the first channel signal of the current frame based on the inter-channel time difference of the current frame, if it is determined that the sign of the inter-channel time difference of the current frame is different from the sign of the inter-channel time difference of the previous frame. a processing unit 1402 configured to perform delay alignment processing and to perform delay alignment processing on the second channel signal of the current frame based on the inter-channel time difference of the previous frame; a processing unit 1042, wherein the signal is the target channel signal of the current frame and the second channel signal is the signal within the stereo signal of the current frame and on the same channel as the target channel of the previous frame; including.

Optionally, processing unit 1402
The signal of the first processing length in the first channel signal of the current frame is changed to the signal of the first alignment processing length to obtain the first channel signal of the current frame after the delay alignment processing. specifically configured to compress,
The first process length is determined based on the inter-channel time difference of the current frame and the first alignment process length, where the first process length is greater than the first alignment process length.

Optionally, the first process length is the sum of the absolute value of the inter-channel time difference of the current frame and the first alignment process length.

Optionally, the starting point of the signal of the first treatment length is located before the starting point of the signal of the first alignment treatment length, such that the starting point of the signal of the first treatment length and the first alignment treatment length is the absolute value of the inter-channel time difference of the current frame.

Optionally, the starting point of the signal of the first alignment process length is located at the starting point of the first channel signal of the current frame or after the starting point of the first channel signal of the current frame, The length between the start point of the alignment process length signal and the end point of the first channel signal of the current frame is greater than or equal to the first alignment process length.

Optionally, the starting point of the signal of the first alignment process length is located before the starting point of the first channel signal of the current frame, and the starting point of the signal of the first alignment process length and the current frame is less than or equal to the transition length, and between the start point of the signal of the first alignment process length and the end point of the first channel signal of the current frame is greater than or equal to the sum of the length of the first alignment process and the transition length, and the transition length is less than or equal to the maximum absolute value of the inter-channel time difference of the current frame.

Optionally, processing unit 1402
To obtain the second channel signal of the current frame after the delay alignment process, the signal of the second process length in the second channel signal of the current frame is changed to the signal of the second alignment process length. specifically configured to stretch,
A second process length is determined based on the inter-channel time difference of the previous frame and a second alignment process length, where the second process length is less than the second alignment process length.

Optionally, the second process length is the difference between the second alignment process length and the absolute value of the inter-channel time difference of the previous frame.

Optionally, the starting point of the signal of the second process length is located after the starting point of the signal of the second alignment process length, and the starting point of the signal of the second process length and the starting point of the second alignment process length The length to the start of the signal is the absolute value of the inter-channel time difference of the previous frame.

Optionally, the starting point of the signal of the second alignment process length is located at the starting point of the second channel signal of the current frame or after the starting point of the second channel signal of the current frame and The length between the start point of the alignment process length signal and the end point of the second channel signal of the current frame is greater than or equal to the second alignment process length.

Optionally, a length between the start of the signal of the second alignment process length and the start of the second channel signal of the current frame is equal to the second preset length and the first alignment process length is equal to the sum of the second preset length and the second alignment process length.

L_next_targetは第1のアライメント処理長であり、cur_itdは現在のフレームのチャンネル間時間差であり、prev_itdは前のフレームのチャンネル間時間差であり、Lは遅延アライメント処理の処理長である。 Optionally, the first alignment process length is less than or equal to the frame length of the current frame, and the first alignment process length is a preset length; fill,

L_next_target is the first alignment process length, cur_itd is the inter-channel time difference of the current frame, prev_itd is the inter-channel time difference of the previous frame, and L is the process length of the delayed alignment process.

L_pre_targetは第2のアライメント処理長であり、cur_itdは現在のフレームのチャンネル間時間差であり、prev_itdは前のフレームのチャンネル間時間差であり、Lは遅延アライメント処理の処理長である。 Optionally, the second alignment process length is less than or equal to the frame length of the current frame, and the second alignment process length is a preset length; fill,

L_pre_target is the length of the second alignment process, cur_itd is the inter-channel time difference of the current frame, prev_itd is the inter-channel time difference of the previous frame, and L is the process length of the delayed alignment process.

Lは遅延アライメント処理の処理長であり、MAX_DELAY_CHANGEは隣接するフレームのチャンネル間時間差の間の最大差分値であり、L_initは遅延アライメント処理のプリセット処理長である。 Optionally, the process length of the delayed alignment process is less than or equal to the frame length of the current frame, and the process length of the delayed alignment process is a preset length; fill,

L is the processing length of the delay alignment process, MAX_DELAY_CHANGE is the maximum difference value between the inter-channel time differences of adjacent frames, and L_init is the preset process length of the delay alignment process.

Based on the same technical concept, the embodiments of this application further provide a stereo signal processing device, and the stereo signal processing device may perform the steps of the method in FIG.

As shown in FIG. 15, the embodiment of this application provides a schematic structural diagram of a stereo signal processing device.

Referring to FIG. 15, stereo signal processing apparatus 1500 includes processor 1501 and memory 1502 .

Memory 1052 stores executable instructions, which are sent to processor 1501 to perform the following steps:
The step of performing delay estimation on the current frame stereo signal to determine the current frame inter-channel time difference, wherein the current frame inter-channel time difference is between the current frame first channel signal and a step, which is the time difference between the current frame and the second channel signal;
For the first channel signal of the current frame based on the inter-channel time difference of the current frame, if the sign of the inter-channel time difference of the current frame is different from the sign of the inter-channel time difference of the frame before the current frame performing delay alignment processing and performing delay alignment processing on the second channel signal of the current frame based on the inter-channel time difference of the previous frame, wherein the first channel signal is the current frame's A target channel signal, a second channel signal, on the same channel as the target channel signal of the previous frame, is used to command the steps to be performed.

Optionally, the executable instructions direct the processor 1501 to perform the following steps when performing delay alignment processing on the first channel signal of the current frame based on the inter-channel time difference of the current frame: ,
The signal of the first processing length in the first channel signal of the current frame is changed to the signal of the first alignment processing length to obtain the first channel signal of the current frame after the delay alignment processing. a step of compressing;
The first process length is determined based on the inter-channel time difference of the current frame and the first alignment process length, wherein the first process length is greater than the first alignment process length, so as to perform the step used to command.

Optionally, the first process length is the sum of the absolute value of the inter-channel time difference of the current frame and the first alignment process length.

Optionally, the starting point of the signal of the first treatment length is located before the starting point of the signal of the first alignment treatment length, such that the starting point of the signal of the first treatment length and the first alignment treatment length is the absolute value of the inter-channel time difference of the current frame.

Optionally, the starting point of the signal of the first alignment process length is located at the starting point of the first channel signal of the current frame or after the starting point of the first channel signal of the current frame, The length between the start point of the alignment process length signal and the end point of the first channel signal of the current frame is greater than or equal to the first alignment process length.

Optionally, the starting point of the signal of the first alignment process length is located before the starting point of the first channel signal of the current frame, and the starting point of the signal of the first alignment process length and the current frame is less than or equal to the transition length, and between the start point of the signal of the first alignment process length and the end point of the first channel signal of the current frame is greater than or equal to the sum of the length of the first alignment process and the transition length, and the transition length is less than or equal to the maximum absolute value of the inter-channel time difference of the current frame.

Optionally, the executable instructions, when performing delay alignment processing on the second channel signal of the current frame based on the inter-channel time difference of the previous frame, instruct the processor 1501 to perform the following steps: ,
To obtain the second channel signal of the current frame after the delay alignment process, the signal of the second process length in the second channel signal of the current frame is changed to the signal of the second alignment process length. a step of stretching,
A second process length is determined based on the inter-channel time difference of the previous frame and a second alignment process length, wherein the second process length is less than the second alignment process length, to perform the step used to command.

Optionally, the second process length is the difference between the second alignment process length and the absolute value of the inter-channel time difference of the previous frame.

Optionally, the starting point of the signal of the second process length is located after the starting point of the signal of the second alignment process length, and the starting point of the signal of the second process length and the starting point of the second alignment process length The length to the start of the signal is the absolute value of the inter-channel time difference of the previous frame.

Optionally, the starting point of the signal of the second alignment process length is located at the starting point of the second channel signal of the current frame or after the starting point of the second channel signal of the current frame and The length between the start point of the alignment process length signal and the end point of the second channel signal of the current frame is greater than or equal to the second alignment process length.

Optionally, a length between the start of the signal of the second alignment process length and the start of the second channel signal of the current frame is equal to the second preset length and the first alignment process length is equal to the sum of the second preset length and the second alignment process length.

L_next_targetは第1のアライメント処理長であり、cur_itdは現在のフレームのチャンネル間時間差であり、prev_itdは前のフレームのチャンネル間時間差であり、Lは遅延アライメント処理の処理長である。 Optionally, the first alignment process length is less than or equal to the frame length of the current frame, and the first alignment process length is a preset length; fill,

L_next_target is the first alignment process length, cur_itd is the inter-channel time difference of the current frame, prev_itd is the inter-channel time difference of the previous frame, and L is the process length of the delayed alignment process.

L_pre_targetは第2のアライメント処理長であり、cur_itdは現在のフレームのチャンネル間時間差であり、prev_itdは前のフレームのチャンネル間時間差であり、Lは遅延アライメント処理の処理長である。 Optionally, the second alignment process length is less than or equal to the frame length of the current frame, and the second alignment process length is a preset length; fill,

L_pre_target is the length of the second alignment process, cur_itd is the inter-channel time difference of the current frame, prev_itd is the inter-channel time difference of the previous frame, and L is the process length of the delayed alignment process.

Lは遅延アライメント処理の処理長であり、MAX_DELAY_CHANGEは隣接するフレームのチャンネル間時間差の間の最大差分値であり、L_initは遅延アライメント処理のプリセット処理長である。 Optionally, the process length of the delayed alignment process is less than or equal to the frame length of the current frame, and the process length of the delayed alignment process is a preset length; fill,

L is the processing length of the delay alignment process, MAX_DELAY_CHANGE is the maximum difference value between the inter-channel time differences of adjacent frames, and L_init is the preset process length of the delay alignment process.

Based on the same technical concept, the embodiments of this application further provide a stereo signal processing device, and the stereo signal processing device may perform the steps of the method in FIG.

As shown in FIG. 16, the embodiment of this application provides a schematic structural diagram of a stereo signal processing device.

Referring to FIG. 16, the stereo signal processing device 1600 includes:
a transceiver unit 1601 configured to determine an inter-channel time difference for the current frame based on the received codestream;
If the sign of the inter-channel time difference of the current frame is different from the sign of the inter-channel time difference of the previous frame, perform delay recovery processing on the first channel signal of the current frame based on the inter-channel time difference of the current frame. and perform delay recovery processing on the second channel signal of the current frame based on the inter-channel time difference of the previous frame, wherein the first channel signal is the current and a processing unit 1602, wherein the second channel signal is the target channel signal of the first frame and the second channel signal is the signal that is within the stereo signal of the current frame and on the same channel as the target channel of the previous frame.

Optionally, processing unit 1602
The signal of the third processing length in the first channel signal of the current frame is combined with the signal of the third alignment processing length to obtain the first channel signal of the current frame after delay recovery processing. specifically configured to stretch,
A third process length is determined based on the inter-channel time difference of the current frame and a third alignment process length, where the third process length is less than the third alignment process length.

Optionally, the third process length is the difference between the third alignment process length and the absolute value of the inter-channel time difference of the current frame.

Optionally, the starting point of the signal of the third process length is located after the starting point of the signal of the third alignment process length, and the starting point of the signal of the third process length and the starting point of the third alignment process length The length to the start of the signal is the absolute value of the inter-channel time difference of the current frame.

Optionally, the starting point of the signal of the third processing length is located at the starting point of the first channel signal of the current frame or after the starting point of the first channel signal of the current frame and The length between the start point of the signal of the process length and the end point of the first channel signal of the current frame is the difference between the third alignment process length and the absolute value of the inter-channel time difference of the current frame That's it.

Optionally, processing unit 1602
The signal of the fourth processing length in the second channel signal of the current frame is combined with the signal of the fourth alignment processing length to obtain the second channel signal of the current frame after delay recovery processing. specifically configured to compress,
A fourth process length is determined based on the inter-channel time difference of the previous frame and a fourth alignment process length, where the fourth process length is greater than the fourth alignment process length.

Optionally, the fourth process length is the sum of the absolute value of the inter-channel time difference of the previous frame and the fourth alignment process length.

Optionally, the starting point of the signal of the fourth process length is located before the starting point of the signal of the fourth alignment process length, such that the starting point of the signal of the fourth process length and the fourth alignment process length is the absolute value of the inter-channel time difference of the previous frame.

Optionally, the starting point of the signal of the fourth alignment process length is located at the starting point of the second channel signal of the current frame or after the starting point of the second channel signal of the current frame, The length between the start point of the alignment process length signal and the end point of the second channel signal of the current frame is greater than or equal to the fourth alignment process length.

Optionally, the length between the starting point of the signal of the fourth alignment process length and the starting point of the second channel signal of the current frame is equal to the fourth preset length and the third alignment process length is equal to the sum of the fourth preset length and the fourth alignment process length.

L2_next_targetは第3のアライメント処理長であり、cur_itdは現在のフレームのチャンネル間時間差であり、prev_itdは前のフレームのチャンネル間時間差であり、Lは遅延アライメント処理の処理長である。 Optionally, the third alignment process length is less than or equal to the frame length of the current frame, and the third alignment process length is a preset length; fill,

L2_next_target is the length of the third alignment process, cur_itd is the inter-channel time difference of the current frame, prev_itd is the inter-channel time difference of the previous frame, and L is the process length of the delayed alignment process.

L2_pre_targetは第4のアライメント処理長であり、cur_itdは現在のフレームのチャンネル間時間差であり、prev_itdは前のフレームのチャンネル間時間差であり、Lは遅延アライメント処理の処理長である。 Optionally, the fourth alignment process length is less than or equal to the frame length of the current frame, and the fourth alignment process length is a preset length; fill,

L2_pre_target is the length of the fourth alignment process, cur_itd is the inter-channel time difference of the current frame, prev_itd is the inter-channel time difference of the previous frame, and L is the process length of the delay alignment process.

Lは遅延アライメント処理の処理長であり、MAX_DELAY_CHANGEは隣接するフレームのチャンネル間時間差の間の最大差分値であり、L_initは遅延アライメント処理のプリセット処理長である。 Optionally, the process length of the delayed alignment process is less than or equal to the frame length of the current frame, and the process length of the delayed alignment process is a preset length; fill,

L is the processing length of the delay alignment process, MAX_DELAY_CHANGE is the maximum difference value between the inter-channel time differences of adjacent frames, and L_init is the preset process length of the delay alignment process.

Based on the same technical concept, the embodiments of this application further provide a stereo signal processing device, and the stereo signal processing device may perform the steps of the method in FIG.

As shown in FIG. 17, the embodiment of this application provides a schematic structural diagram of a stereo signal processing device.

Referring to FIG. 17, stereo signal processing device 1700 includes processor 1701 and memory 1702 .

Memory 1702 stores executable instructions, which are sent to processor 1701 to perform the following steps:
determining the inter-channel time difference of the current frame based on the received codestream, wherein the inter-channel time difference of the current frame is the difference between the first channel signal of the current frame and the second channel signal of the current frame; a step, which is the time difference between
For the first channel signal of the current frame based on the inter-channel time difference of the current frame, if the sign of the inter-channel time difference of the current frame is different from the sign of the inter-channel time difference of the frame before the current frame performing delay recovery processing, performing delay recovery processing on the second channel signal of the current frame based on the inter-channel time difference of the previous frame, wherein the first channel signal is the current frame's A target channel signal, a second channel signal, on the same channel as the target channel signal of the previous frame, is used to command the steps to be performed.

Optionally, the executable instructions, when performing delay recovery processing on the first channel signal of the current frame based on the inter-channel time difference of the current frame, instruct the processor 1701 to perform the following steps: ,
The signal of the third processing length in the first channel signal of the current frame is combined with the signal of the third alignment processing length to obtain the first channel signal of the current frame after delay recovery processing. a step of stretching,
A third process length is determined based on the inter-channel time difference of the current frame and a third alignment process length, wherein the third process length is less than the third alignment process length, to perform step used to command.

Optionally, the third process length is the difference between the third alignment process length and the absolute value of the inter-channel time difference of the current frame.

Optionally, the starting point of the signal of the third process length is located after the starting point of the signal of the third alignment process length, and the starting point of the signal of the third process length and the starting point of the third alignment process length The length to the start of the signal is the absolute value of the inter-channel time difference of the current frame.

Optionally, the starting point of the signal of the third processing length is located at the starting point of the first channel signal of the current frame or after the starting point of the first channel signal of the current frame and The length between the start point of the signal of the process length and the end point of the first channel signal of the current frame is the difference between the third alignment process length and the absolute value of the inter-channel time difference of the current frame That's it.

Optionally, the executable instructions, when performing delay recovery processing on the second channel signal of the current frame based on the inter-channel time difference of the previous frame, instruct the processor 1701 to perform the following steps: ,
The signal of the fourth processing length in the second channel signal of the current frame is combined with the signal of the fourth alignment processing length to obtain the second channel signal of the current frame after delay recovery processing. a step of compressing;
A fourth process length is determined based on the inter-channel time difference of the previous frame and a fourth alignment process length, wherein the fourth process length is greater than the fourth alignment process length, so as to perform step used to command.

Optionally, the fourth process length is the sum of the absolute value of the inter-channel time difference of the previous frame and the fourth alignment process length.

Optionally, the starting point of the signal of the fourth process length is located before the starting point of the signal of the fourth alignment process length, such that the starting point of the signal of the fourth process length and the fourth alignment process length is the absolute value of the inter-channel time difference of the previous frame.

Optionally, the starting point of the signal of the fourth alignment process length is located at the starting point of the second channel signal of the current frame or after the starting point of the second channel signal of the current frame, The length between the start point of the alignment process length signal and the end point of the second channel signal of the current frame is greater than or equal to the fourth alignment process length.

Optionally, the length between the starting point of the signal of the fourth alignment process length and the starting point of the second channel signal of the current frame is equal to the fourth preset length and the third alignment process length is equal to the sum of the fourth preset length and the fourth alignment process length.

Embodiments of this application further provide a computer-readable storage medium configured to store computer software instructions that need to be executed by the processor described above. Computer software instructions include programs that need to be executed by the processors described above.

Those skilled in the art should understand that the embodiments of this application may be provided as a method, system or computer program product. Accordingly, this application may use the form of hardware-only embodiments, software-only embodiments, or embodiments having a combination of software and hardware. Further, this application uses the form of a computer program product embodied on one or more computer-usable storage media (including, but not limited to, disk memory, optical memory, etc.) containing computer-usable program code. may

This application has been described with reference to flowchart illustrations and/or block diagrams of methods, devices (systems) and computer program products according to this application. Computer program instructions may be used to implement each process and/or each block in the flowchart and/or block diagrams, and combinations of processes and/or blocks in the flowchart and/or block diagrams. should be understood. These computer program instructions may be provided to a processor of a general purpose computer, special purpose computer, embedded processor, or any other programmable data processing device for producing a machine, thereby rendering the computer or any Instructions executed by processors of other programmable data processing devices produce apparatus for performing specified functions in one or more processes in the flowcharts and/or one or more blocks in the block diagrams.

These computer program instructions may be stored in a computer readable memory capable of instructing a computer, or any other programmable data processing device, to operate in a particular manner, thereby rendering the computer readable memory The instructions stored in generate artifacts containing instruction units. An instruction unit implements the specified functionality in one or more processes in the flowcharts and/or one or more blocks in the block diagrams.

Obviously, those skilled in the art can make various modifications and changes to this application without departing from the scope of this application. This application intends to cover these modifications and variations provided they fall within the scope of protection defined by the claims.

Optionally, the starting point of the signal of the first alignment process length is located before the starting point of the first channel signal of the current frame, and the starting point of the signal of the first alignment process length and the current frame is less than or equal to the transition section length, and the length between the start point of the signal of the first alignment processing length and the end point of the first channel signal of the current frame is The interval length is greater than or equal to the sum of the first alignment process length and the transition interval length, and the transition interval length is less than or equal to the absolute value of the inter-channel time difference of the current frame.

Optionally, the starting point of the signal of the first alignment process length is located before the starting point of the first channel signal of the current frame, and the starting point of the signal of the first alignment process length and the current frame is less than or equal to the transition section length, and the length between the start point of the signal of the first alignment processing length and the end point of the first channel signal of the current frame is The interval length is greater than or equal to the sum of the first alignment process length and the transition interval length, and the transition interval length is less than or equal to the absolute value of the inter-channel time difference of the current frame.

In FIG. 4, the frame length of the current frame is N, the starting point of the first channel signal of the current frame is B1=0, and the ending point of the first channel signal of the current frame is E1=N. -1. The starting point D1 of the first alignment process length is located before the starting point B1 of the first channel signal of the current frame, and the starting point D1 of the signal of the first alignment process length and the first channel signal of the current frame The length between the start point B1 of the channel signal of the current frame and the start point B1 of the channel signal of the current frame is equal to or less than the transition interval length, and the length between the start point D1 of the signal of the first alignment processing length and the end point E1 of the first channel signal of the current frame The length of the interval is greater than or equal to the sum of the length of the first alignment process and the length of the transition section . For ease of explanation, in this embodiment of this application and in FIG. 4, the transition interval length is denoted by ts. In this case D1=B1-ts. The end point of the signal of the first alignment process length is C1, and the length from the start point D1 to the end point C1 is equal to the first alignment process length, C1=D1+L_next_target-1.

In FIG. 4, for the sake of explanation, the length between the starting point D1 of the signal of the first alignment processing length and the starting point B1 of the first channel signal of the current frame is equal to the transition section length. Note that it is used as an example. the length between the starting point D1 of the signal of the first alignment process length and the starting point B1 of the first channel signal of the current frame may alternatively be less than the transition interval length, D1<B1, and D1>B1. For the case of less than the transition section length, refer to the description here. No further details are given.

FIG. 5 is a schematic diagram of stereo signal processing according to an embodiment of this application. In FIG. 5, for ease of explanation, a point in the second channel signal before the delay alignment process and a point in the second channel signal after the decompression process at the same position have the same coordinates. This does not mean that the signals of points with the same coordinates are the same. For example, both coordinates of the starting point of the second channel signal of the current frame are marked as B2 before the delay alignment process and after the decompression process.

Finally, in the second channel signal after decompression process, the N sampling points starting from the starting point B2 are used as the second channel signal of the current frame after delay alignment process. That is, the starting point of the second channel signal of the current frame after delay alignment processing is point B2, and the ending point is E2.

MAX_DELAY_CHANGE is a positive integer greater than 0 and may be less than or equal to |T _max -T _min |. T _max corresponds to the maximum inter-channel time difference at the current sampling rate, and T _min corresponds to the minimum inter-channel time difference at the current sampling rate. For example, MAX_DELAY_CHANGE equals 80, 40 or 20. MAX_DELAY_CHANGE may be 20 in the embodiment of this application.

If abs(cur_itd) is less than abs(prev_itd), the signal from point B+abs(prev_itd)-abs(cur_itd) to point B+L-1 of the buffered target channel signal is L points , which are used as the signals of the first L points of the target channel signal after the decompression process. The signal from point B+L to point B+N-1 in the target channel signal is directly used as the signal from point B+L to point B+N-1 in the target channel signal after expansion processing . The signal at point abs(cur_itd) is manually reconstructed based on the reference channel signal as the signal from point B+N to point B+N+abs(cur_itd)-1 of the target channel signal after stretching used. The N-point signal starting from point B+abs(cur_itd) in the target channel signal after decompression process is used as the target channel signal of the current frame after delay alignment process. The current frame reference channel signal is used directly as the current frame reference channel signal after delay alignment processing. B represents the coordinates of the starting point in the target channel signal of the current frame, N represents the frame length of the current frame, and L represents the process length of the delay alignment process.

If abs(cur_itd) is greater than abs(prev_itd), the signal from point B+abs(prev_itd)-abs(cur_itd) of the buffered target channel signal to point B+L-1 is L points is compressed into a signal of length , which is used as the signal of the first L points of the target channel signal after the compression process. The signal from point B+L to point B+N-1 in the target channel signal is directly used as the signal from point B+L to point B+N-1 in the target channel signal after compression processing . The signal at point abs(cur_itd) is manually reconstructed based on the reference channel signal as the signal from point B+N to point B+N+abs(cur_itd)-1 of the target channel signal after compression processing. used. The N-point signal starting from point B+abs(cur_itd) in the target channel signal after compression process is used as the target channel signal of the current frame after delay alignment process. The current frame reference channel signal is used directly as the current frame reference channel signal after delay alignment processing. B represents the coordinates of the starting point in the target channel signal of the current frame, N represents the frame length of the current frame, and L represents the process length of the delay alignment process.

If abs(cur_itd) is less than abs(prev_itd), the signal from point B-ts+abs(prev_itd)-abs(cur_itd) to point B+L-ts-1 of the buffered target channel signal is L-length signal, which is used as the signal from point B-ts to point B+L-ts-1 of the target channel signal after the stretching process. The signal from the point B+L-ts to the point B+N-Ts2-1 in the target channel signal is the point B+L-ts to the point B+N-Ts2-1 in the target channel signal after decompression. used directly as a signal to The signal at point Ts2 is generated based on the reference channel signal and the target channel signal, and is used as the signal from point B+N-Ts2 to point B+N-1 of the target channel signal after decompression processing. The signal at point abs(cur_itd) is manually reconstructed based on the reference channel signal as the signal from point B+N to point B+N+abs(cur_itd)-1 of the target channel signal after stretching used. The N-point signal starting from point B+abs(cur_itd) in the target channel signal after decompression process is used as the target channel signal of the current frame after delay alignment process. The current frame reference channel signal is used directly as the current frame reference channel signal after delay alignment processing. B represents the coordinates of the starting point in the target channel signal of the current frame, N represents the frame length of the current frame, and L represents the process length of the delay alignment process.

If abs(cur_itd) is greater than abs(prev_itd), the signal from point B-ts+abs(prev_itd)-abs(cur_itd) to point B+L-ts-1 of the buffered target channel signal is Compressed into a signal of length L points, which is used as the signal from point B-ts to point B+L-ts-1 of the target channel signal after the compression process. The signal from point B+L-ts to point B+N-Ts2-1 in the target channel signal is the signal from point B+L-ts to point B+N-Ts2-1 in the target channel signal after compression processing. used directly as a signal to The signal at point Ts2 is generated based on the reference channel signal and the target channel signal, and is used as the signal from point B+N-Ts2 to point B+N-1 of the target channel signal after compression processing. The signal at point abs(cur_itd) is manually reconstructed based on the reference channel signal and used as the signal from point B+N to point B+N+abs(cur_itd)-1 of the target channel after compression processing be done. The N-point signal starting from point B+abs(cur_itd) in the target channel signal after compression process is used as the target channel signal of the current frame after delay alignment process. The current frame reference channel signal is used directly as the current frame reference channel signal after delay alignment processing. B represents the coordinates of the starting point in the target channel signal of the current frame, N represents the frame length of the current frame, and L represents the process length of the delay alignment process.

The signal of point Ts2 is generated based on the reference channel signal and the target channel signal, and is used as the signal from point B+N-Ts2 to point B+N-1 of the target channel signal after compression or decompression processing. may be specifically as follows. The signal at point Ts2 is the signal from point B+N-Ts2 to point B+N-1 on the target channel and the signal from point B+N-abs(cur_itd)-Ts2 to point B+N-abs(cur_itd) on the reference channel. )-1 and used as the signals from point B+N-Ts2 to point B+N-1 of the target channel signal after compression or decompression. The signal at point abs(cur_itd) is manually reconstructed based on the reference channel signal, and the signal from point B+N to point B+N+abs(cur_itd)-1 of the target channel after compression or decompression processing may be specifically as follows. The signal at point abs(cur_itd) is generated based on the signals from point B+N-abs(cur_itd) of the reference channel to point B+N-1, and point B of the target channel signal after compression or decompression processing. Used as signal from +N to point B+N+abs(cur_itd)-1.

In FIG. 10, the length between the starting point D3 of the signal of the third processing length and the starting point B3 of the first channel signal of the current frame is the third preset length, and the third alignment processing The starting point of the long signal is A3 , where A3 =D3-abs(cur_itd). H3 is located before the starting point B3 of the first channel signal of the current frame, the length between H3 and A3 is the third preset length, the length between H3 and B3 is the absolute value of the inter-channel time difference of the current frame, ie H3=B3-abs(cur_itd).

Referring to FIG. 14, the stereo signal processing device 1400 includes:
a delay estimation unit 1401 configured to perform delay estimation based on the stereo signal of the current frame to determine the inter-channel time difference of the current frame;
for the first channel signal of the current frame based on the inter-channel time difference of the current frame, if it is determined that the sign of the inter-channel time difference of the current frame is different from the sign of the inter-channel time difference of the previous frame. a processing unit 1402 configured to perform delay alignment processing and to perform delay alignment processing on the second channel signal of the current frame based on the inter-channel time difference of the previous frame; The signal is the target channel signal of the current frame and the second channel signal is the signal within the stereo signal of the current frame and on the same channel as the target channel signal of the previous frame, processing unit 1042 Including and .

Optionally, the starting point of the signal of the first alignment process length is located before the starting point of the first channel signal of the current frame, and the starting point of the signal of the first alignment process length and the current frame is less than or equal to the transition section length, and the length between the start point of the signal of the first alignment processing length and the end point of the first channel signal of the current frame is The interval length is greater than or equal to the sum of the first alignment process length and the transition interval length, and the transition interval length is less than or equal to the absolute value of the inter-channel time difference of the current frame.

Optionally, the starting point of the signal of the first alignment process length is located before the starting point of the first channel signal of the current frame, and the starting point of the signal of the first alignment process length and the current frame is less than or equal to the transition section length, and the length between the start point of the signal of the first alignment processing length and the end point of the first channel signal of the current frame is The interval length is greater than or equal to the sum of the first alignment process length and the transition interval length, and the transition interval length is less than or equal to the absolute value of the inter-channel time difference of the current frame.

Referring to FIG. 16, the stereo signal processing device 1600 includes:
a transceiver unit 1601 configured to determine an inter-channel time difference for the current frame based on the received codestream;
If the sign of the inter-channel time difference of the current frame is different from the sign of the inter-channel time difference of the previous frame, perform delay recovery processing on the first channel signal of the current frame based on the inter-channel time difference of the current frame. and perform delay recovery processing on the second channel signal of the current frame based on the inter-channel time difference of the previous frame, wherein the first channel signal is the current and a processing unit 1602, wherein the second channel signal is the target channel signal of the first frame and the second channel signal is the signal that is within the stereo signal of the current frame and on the same channel as the target channel signal of the previous frame.

Claims (40)

A stereo signal processing method comprising:
performing delay estimation on a stereo signal of said current frame to determine an inter-channel time difference of said current frame, said inter-channel time difference of said current frame being the first is the time difference between the channel signal of the current frame and the second channel signal of the current frame;
If the sign of the inter-channel time difference of the current frame is different from the sign of the inter-channel time difference of the frame previous to the current frame, then the second channel time difference of the current frame is based on the inter-channel time difference of the current frame. performing delay alignment processing on one channel signal and performing delay alignment processing on the second channel signal of the current frame based on the inter-channel time difference of the previous frame; wherein the first channel signal is the target channel signal of the current frame and the second channel signal is on the same channel as the target channel signal of the previous frame. performing delay alignment processing on the first channel signal of the current frame based on the inter-channel time difference of the current frame;
performing a first alignment process on a signal of a first process length within the first channel signal of the current frame to obtain the first channel signal of the current frame after delay alignment process; compressed to a longer signal,
The first process length is determined based on the inter-channel time difference of the current frame and the first alignment process length, wherein the first process length is greater than the first alignment process length. 2. The method of claim 1, comprising: 3. The method of claim 2, wherein the first process length is the sum of the absolute value of the inter-channel time difference of the current frame and the first alignment process length. The starting point of the signal of the first process length is located before the starting point of the signal of the first alignment process length, and the starting point of the signal of the first process length and the first alignment process length are located before the starting point of the signal of the first alignment process length. 4. The method of claim 3, wherein the length between the starting point of the signal for an alignment process length of is the absolute value of the inter-channel time difference of the current frame. The starting point of the signal of the first alignment process length is located at the starting point of the first channel signal of the current frame or after the starting point of the first channel signal of the current frame. , a length between the starting point of the signal of the first alignment length and the ending point of the first channel signal of the current frame is greater than or equal to the first alignment length. Item 3. The method according to item 3. The starting point of the signal of the first alignment length is located before the starting point of the first channel signal of the current frame and is the starting point of the signal of the first alignment length. A length between the starting point of the first channel signal of the current frame is less than or equal to a transition length, and the starting point of the signal of the first alignment process length and the starting point of the current frame. The length between the end point of the first channel signal is equal to or greater than the sum of the first alignment process length and the transition length, and the transition length is the inter-channel time difference of the current frame. 4. The method of claim 3, which is less than or equal to the maximum absolute value. performing delay alignment processing on the second channel signal of the current frame based on the inter-channel time difference of the previous frame;
performing a second alignment process on a signal of a second processing length within the second channel signal of the current frame to obtain the second channel signal of the current frame after delay alignment process; to a longer signal,
The second processing length is determined based on the inter-channel time difference of the previous frame and the second alignment processing length, and the second processing length is less than the second alignment processing length. 7. The method of any one of claims 1-6, comprising: 8. The method of claim 7, wherein the second process length is the difference between the second alignment process length and the absolute value of the inter-channel time difference of the previous frame. The starting point of the signal of the second process length is located after the starting point of the signal of the second alignment process length, and the starting point of the signal of the second process length and the second alignment process length are positioned after the starting point of the signal of the second alignment process length. 9. The method of claim 8, wherein the length of the alignment process length between the starting point of the signal is the absolute value of the inter-channel time difference of the previous frame. The starting point of the signal of the second alignment process length is located at the starting point of the second channel signal of the current frame or after the starting point of the second channel signal of the current frame. , a length between the start point of the signal of the second alignment length and the end point of the second channel signal of the current frame is greater than or equal to the second alignment length. Item 8. The method according to item 8. A length between the starting point of the signal of the second alignment process length and the starting point of the second channel signal of the current frame is equal to a second preset length, and the first The length between the starting point of the signal of the alignment process length and the starting point of the first channel signal of the current frame is equal to the length between the second preset length and the second alignment process length. 11. A method according to any one of claims 7-10, equal to the sum. The first alignment process length is less than or equal to the frame length of the current frame, and the first alignment process length is a preset length, or the first alignment process length is: fill,

L_next_target is the first alignment process length, cur_itd is the inter-channel time difference of the current frame, prev_itd is the inter-channel time difference of the previous frame, and L is the process length of the delayed alignment process. A method according to any one of claims 2 to 11. The second alignment process length is less than or equal to the frame length of the current frame, and the second alignment process length is a preset length; The filling,

L_pre_target is the second alignment process length, cur_itd is the inter-channel time difference of the current frame, prev_itd is the inter-channel time difference of the previous frame, and L is the process length of a delayed alignment process. 13. The method of any one of claims 7-12, wherein The process length of a delayed alignment process is less than or equal to the frame length of the current frame, and the process length of a delayed alignment process is a preset length, or the process length of a delayed alignment process is determined by the following formula: The filling,

14. The method of claim 12 or 13, wherein L is the processing length of delay alignment processing, MAX_DELAY_CHANGE is the maximum difference value between inter-channel time differences of adjacent frames, and L_init is a preset processing length of delay alignment processing. Method. A stereo signal processing method comprising:
determining an inter-channel time difference of a current frame based on a received codestream, wherein the inter-channel time difference of the current frame is a first channel signal of the current frame and a second channel signal of the current frame; a step, which is the time difference between the channel signals of
If the sign of the inter-channel time difference of the current frame is different from the sign of the inter-channel time difference of the frame previous to the current frame, then the second channel time difference of the current frame is based on the inter-channel time difference of the current frame. performing delay recovery processing on one channel signal and performing delay recovery processing on the second channel signal of the current frame based on the inter-channel time difference of the previous frame; wherein the first channel signal is the target channel signal of the current frame and the second channel signal is on the same channel as the target channel signal of the previous frame. performing delay recovery processing on the first channel signal of the current frame based on the inter-channel time difference of the current frame;
performing a third alignment process on a signal of a third process length within the first channel signal of the current frame to obtain the first channel signal of the current frame after delay recovery process; to a longer signal,
The third process length is determined based on the inter-channel time difference of the current frame and the third alignment process length, wherein the third process length is less than the third alignment process length. 16. The method of claim 15, comprising: 17. The method of claim 16, wherein the third process length is the difference between the third alignment process length and the absolute value of the inter-channel time difference of the current frame. The starting point of the signal of the third process length is located after the starting point of the signal of the third alignment process length, and the starting point of the signal of the third process length and the third alignment process length are positioned after the starting point of the signal of the third alignment process length. 18. The method of claim 17, wherein the length of the alignment process length between the starting point of the signal is the absolute value of the inter-channel time difference of the current frame. The starting point of the signal of the third processing length is located at or after the starting point of the first channel signal of the current frame. , the length between the starting point of the signal of the third process length and the ending point of the first channel signal of the current frame is equal to the length of the third alignment process length and the current frame; 19. The method of claim 18, wherein said difference between said absolute value of said inter-channel time difference is greater than or equal to said difference. performing delay recovery processing on the second channel signal of the current frame based on the inter-channel time difference of the previous frame;
performing a fourth alignment process on a signal of a fourth process length within the second channel signal of the current frame to obtain the second channel signal of the current frame after delay recovery process; compressed to a longer signal,
The fourth processing length is determined based on the inter-channel time difference of the previous frame and the fourth alignment processing length, and the fourth processing length is greater than the fourth alignment processing length. 17. A method according to claim 15 or 16, comprising 21. The method of claim 20, wherein the fourth process length is the sum of the absolute value of the inter-channel time difference of the previous frame and the fourth alignment process length. The starting point of the signal of the fourth process length is located before the starting point of the signal of the fourth alignment process length, and the starting point of the signal of the fourth process length and the fourth alignment process length are positioned before the starting point of the signal of the fourth alignment process length. 22. The method of claim 21, wherein the length between the starting point of the signal for an alignment process length of is the absolute value of the inter-channel time difference of the previous frame. The starting point of the signal of the fourth alignment length is located at or after the starting point of the second channel signal of the current frame. and a length between the start point of the signal of the fourth alignment length and the end point of the second channel signal of the current frame is greater than or equal to the fourth alignment length. 23. The method of claim 22. a length between the starting point of the signal of the fourth alignment process length and the starting point of the second channel signal of the current frame is equal to a fourth preset length; The length between the starting point of the signal of the alignment process length and the starting point of the first channel signal of the current frame is equal to the length between the fourth preset length and the fourth alignment process length. 24. A method according to any one of claims 20-23, equal to the sum. A stereo signal processing device comprising a processor and memory,
The memory stores executable instructions, which are sent to the processor to perform the following steps:
performing delay estimation on a stereo signal of said current frame to determine an inter-channel time difference of said current frame, said inter-channel time difference of said current frame being the first is the time difference between the channel signal of the current frame and the second channel signal of the current frame;
If the sign of the inter-channel time difference of the current frame is different from the sign of the inter-channel time difference of the frame previous to the current frame, then the second channel time difference of the current frame is based on the inter-channel time difference of the current frame. performing delay alignment processing on one channel signal and performing delay alignment processing on the second channel signal of the current frame based on the inter-channel time difference of the previous frame; wherein the first channel signal is the target channel signal of the current frame and the second channel signal is on the same channel as the target channel signal of the previous frame. A device used to The executable instructions, when performing delay alignment processing on the first channel signal of the current frame based on the inter-channel time difference of the current frame, instruct the processor to perform the following steps: i.e.
performing a first alignment process on a signal of a first process length within the first channel signal of the current frame to obtain the first channel signal of the current frame after delay alignment process; a step of compressing to a long signal,
the first process length is determined based on the inter-channel time difference of the current frame and the first alignment process length, wherein the first process length is greater than the first alignment process length; 26. Apparatus according to claim 25, used for instructing to perform the steps. 27. The apparatus of claim 26, wherein the first process length is the sum of the absolute value of the inter-channel time difference of the current frame and the first alignment process length. The starting point of the signal of the first process length is located before the starting point of the signal of the first alignment process length, and the starting point of the signal of the first process length and the first alignment process length are located before the starting point of the signal of the first alignment process length. 28. The apparatus of claim 27, wherein the length between the starting point of the signal for an alignment process length of is the absolute value of the inter-channel time difference of the current frame. The starting point of the signal of the first alignment process length is located at the starting point of the first channel signal of the current frame or after the starting point of the first channel signal of the current frame. , a length between the starting point of the signal of the first alignment length and the ending point of the first channel signal of the current frame is greater than or equal to the first alignment length. Item 28. Apparatus according to Item 27. The starting point of the signal of the first alignment length is located before the starting point of the first channel signal of the current frame and is the starting point of the signal of the first alignment length. A length between the starting point of the first channel signal of the current frame is less than or equal to a transition length, and the starting point of the signal of the first alignment process length and the starting point of the current frame. The length between the end point of the first channel signal is equal to or greater than the sum of the first alignment process length and the transition length, and the transition length is the inter-channel time difference of the current frame. 28. The apparatus of claim 27, which is less than or equal to the maximum absolute value. The executable instructions, when performing delay alignment processing on the second channel signal of the current frame based on the inter-channel time difference of the previous frame, instruct the processor to perform the following steps: i.e.
performing a second alignment process on a signal of a second processing length within the second channel signal of the current frame to obtain the second channel signal of the current frame after delay alignment process; is the step of decompressing to a signal of length,
The second processing length is determined based on the inter-channel time difference of the previous frame and the second alignment processing length, and the second processing length is less than the second alignment processing length. 31. Apparatus according to any one of claims 26 to 30, used for instructing to perform the steps. 32. The apparatus of claim 31, wherein the second process length is the difference between the second alignment process length and the absolute value of the inter-channel time difference of the previous frame. The starting point of the signal of the second process length is located after the starting point of the signal of the second alignment process length, and the starting point of the signal of the second process length and the second alignment process length are positioned after the starting point of the signal of the second alignment process length. 33. The apparatus of claim 32, wherein the length of alignment process length between said starting point of said signal is said absolute value of said inter-channel time difference of said previous frame. A stereo signal processing device comprising a processor and memory,
The memory stores executable instructions, which are sent to the processor to perform the following steps:
determining an inter-channel time difference of a current frame based on a received codestream, wherein the inter-channel time difference of the current frame is a first channel signal of the current frame and a second channel signal of the current frame; a step, which is the time difference between the channel signals of
If the sign of the inter-channel time difference of the current frame is different from the sign of the inter-channel time difference of the frame previous to the current frame, then the second channel time difference of the current frame is based on the inter-channel time difference of the current frame. performing delay recovery processing on one channel signal and performing delay recovery processing on the second channel signal of the current frame based on the inter-channel time difference of the previous frame; wherein the first channel signal is the target channel signal of the current frame and the second channel signal is on the same channel as the target channel signal of the previous frame. A device used to The executable instructions, when performing delay recovery processing on the first channel signal of the current frame based on the inter-channel time difference of the current frame, instruct the processor to perform the following steps: i.e.
performing a third alignment process on a signal of a third process length within the first channel signal of the current frame to obtain the first channel signal of the current frame after delay recovery process; is the step of decompressing to a signal of length,
the third process length is determined based on the inter-channel time difference of the current frame and the third alignment process length, wherein the third process length is less than the third alignment process length; 35. Apparatus according to claim 34, used for instructing to perform the steps. 36. The apparatus of claim 35, wherein the third process length is the difference between the third alignment process length and the absolute value of the inter-channel time difference of the current frame. The starting point of the signal of the third process length is located after the starting point of the signal of the third alignment process length, and the starting point of the signal of the third process length and the third alignment process length are positioned after the starting point of the signal of the third alignment process length. 37. The apparatus of claim 36, wherein the length of alignment process length between said starting point of said signal is said absolute value of said inter-channel time difference of said current frame. The starting point of the signal of the third processing length is located at or after the starting point of the first channel signal of the current frame. , the length between the starting point of the signal of the third process length and the ending point of the first channel signal of the current frame is equal to the length of the third alignment process length and the current frame; 38. The apparatus of claim 37, which is greater than or equal to said difference between said absolute value of said inter-channel time difference. The executable instructions, when performing delay recovery processing on the second channel signal of the current frame based on the inter-channel time difference of the previous frame, instruct the processor to perform the following steps: i.e.
performing a fourth alignment process on a signal of a fourth process length within the second channel signal of the current frame to obtain the second channel signal of the current frame after delay recovery process; a step of compressing to a long signal,
The fourth processing length is determined based on the inter-channel time difference of the previous frame and the fourth alignment processing length, wherein the fourth processing length is greater than the fourth alignment processing length. 39. Apparatus according to any one of claims 34 to 38, wherein the apparatus is used for instructing to perform the steps. 40. The apparatus of claim 39, wherein the fourth process length is the sum of the absolute value of the inter-channel time difference of the previous frame and the fourth alignment process length.

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